Here are my impressions as beginner (N4~N3 level) who took some Japanese classes at around N5~N4 levels. I think when you are starting from scratch, using some textbook or blog with extensive explanations is required to get a good grasp of the basics.
I am now studying at the N3 level with the Tobira textbook. It turns out that I am not even looking up the grammar sections of Tobira because often explanations of Bunpro are often more detailed. So I think after about N4, I think it’s quite feasible to use only bunpro to expose yourself to new grammar. Nonetheless, I think it’s still essential that you reinforce the grammar points by reading or listening to native material on a regular basis.