Hey @CollinB !
カタカナ is usually used for loan words and onomatopoeia, but you will probably see Japanese words (非外来語) written in katakana from time to time.
There are several reasons why katakana is used instead of kanji.
- The kanji is difficult
- the word using kanji can have a different nuance
- using kanji could make something sound technical
- the kanji sounds too formal
- using katakana/hiragana could is easier to read/ understand
- using katakana would make people think of something they use instead of something technical
For this sentence, katakana is used because it is easier to read and understand, and writing ハサミ would make the readers think of everyday scissors (that normal everyday people use), instead of something that would be used in a professional setting (like medical scissors, or something industrial).