Today, I ran into this video and it made me wonder if it’s one of those language videos that claims that “you can’t say this”, when in fact people actually say it all the time (I really dislike those). Here’s the video:
Of course she’s grammatically correct, but how many times do you hear people use ことだし vs から in real life? Please share your thoughts and experiences.
I don’t know, within the context provided in the video, I think し (and by extension ことだし) do seem to be used a lot more for the very reasons she explains. With just し、there’s less of a cause-and-effect sense compared to ので and から and with ことだし it’s like the speaker is hesitant to single out a single reason for wanting to do something while still sounding objective/logical.
から/ので make sense when there is a single, logical reason for suggesting something, like “Since it’s hot, let’s open the window” etc.
I don’t hear から often (perhaps I do and don’t notice), but I see it quite a bit in study materials and JLPT stuff.
Just an opinion off the top of my head, but it’s possible she’s teaching more real-world conversational Japanese and that sort of thing doesn’t pop up all too often in textbooks and test prep guides.
Not on the exact same level, but I feel like it’s kind of the same reason why study materials for EFL might not teach words like “gonna” or “kinda” despite being used in real-world situations constantly.
Interesting. I have the opposite experience, where I encounter から／ので much more frequently. Not just in textbooks, but also in the real world, when I went to visit Japan recently. It could just be that phenomenon where you don’t start noticing something until you are actively paying attention to it 
.
That said, if ことだし was that common, then why is it placed as an N1 grammar point rather than an N5, or even an N3, grammar point? The “slang” analogy doesn’t hold up in this case, given that ことだし is actually a JLPT grammar point. You can even find it here in BunPro:
And, just to be clear, I get that ことだし is correctly explained in the video (as well as in the BunPro link), and that there are situations where it is more appropriate to use it, as opposed to から／ので. My point is that perhaps, the way から/ので are typically used, is grammatically incorrect yet still common. Similar to how the Potential form has been shorten to れる from られる (at least in the case of いる／える verbs), or how the ている form can be shortened to てる. After all, we do the same thing with our own native language, where we use wrong grammatical structures that are considered normal in every day speech. I’m just thinking that perhaps this is the same situation here?
It seems to be a very common spoken grammar pattern, even though it might be a bit more formal than just using し itself. Search ‘“ことだし” twitter’ on google or on twitter itself and you’ll find a ton of examples of it being used.
Besides, it’s only listed as N1 according to Bunpro, plenty of sites categorize it as N2. And I wouldn’t say that just because it’s placed in a higher JLPT tier that it can’t be a commonly used expression/pattern, just that the context it’s used in might be more limited? I mean, さすが is listed as N2, but you hear that all the time.
It may be a regional difference, too. I live in Hokkaido and I definitely hear から and ので much more frequently than ことだし or even just plain し.
Japan is a surprisingly big place! There’s a lot of variation. I dislike this kind of video because it focuses too much on the little details and intimidates people away from speaking. So long as you can get your point across that’s what really matters.
To add to what was said in the video, から just means ‘because/since’ while ことだし has the nuance of ‘now that(A) has happened, it is a good time to (B)’ (Now that we are done with exams, it is a good opportunity to go to the karaoke), and because of this it is used when the second part of the sentence is usually an invitation, suggestion or an expression of determination. Using から in the sentence given in the video could work, but might sound a little off (not enough for people to correct you in the wild).
Personally I use から when I want to simply say ‘because’, and use ことだし when I want the ‘Now that…’ nuance in there.
Hope this helps! 
This is a much better way of thinking of it, thanks for sharing that!!
I asked a friend and she said it is common to use. I live in Hiroshima area so I hear じゃけ more but から I hear too
Just want to chime in, living in Japan for 5 years now. I rarely hear ことだし. And keep in mind the video title is clickbait. Of course in that situation you can say から, just ことだし has a different nuance and is more polite, so maybe using it with your 先生 like in that scenario is not the best choice (better to use ので) but it’s certainly not wrong
Thanks for sharing your thoughts, everyone!
It seems that each person is going to have a different experience with the frequency of certain words, like this one, as has been mentioned. And I agree that that video is simply being controversial for the sake of views, with a clickbait title, which is unfortunate because I generally enjoy her lessons.
Spanish is my native language, and I’ve seen similar videos where the “teacher” says “NEVER say X. Say Y instead.” I’ve also seen them in English and, while it is true that saying Y sounds more polite, saying X is also fine (even when talking to strangers, which is pretty much the point of those videos). I feel like they’re doing a disservice to language learners because they’re teaching something that is not completely true. Instead, they should explain the reasons why it’s better to say Y, rather than X, without saying “NEVER say X”.