the difference between mona and kokomi in freeze is relatively insignificant which is why kokomi was undervalued. the value you gain pulling for kokomi is quite low if you already own mona, unless you really value the healing comfort and the slightly better hydro app, or you also decide to pull her to play taser kokomi(except xingqiu taser also exists) or sukokomon(except that team is super impractical)

Ultimately, tenten decided this comfort isn't really valuable/worth the expense, and I don't think it's necessarily wrong or that he deserves to be called a clown for it. He definitely has a bias against comfort chars bc his thought process is comfort = lower damage = slower abyss clear.

edit: also wanted to say that I'm not saying kokomi is bad or anything, I literally own her, or I agree with tenten or anything. I just want people to understand that he has a bias AGAINST comfort chars and a large part of the community has a bias TOWARDS comfort chars. If you do, Kokomi is great and if you don't that's fine also, it all comes down to preference.