Personally using Flutter or not is not a question about whether it is good or not.

It is a choice between UX and resources.

If you are targeting a social APP with millions of users, a slight improvement on UX and performance would leads to huge impact on $$$. So go native.

If UX doesn't matter that much, or you don't have enough resources, sure, use Flutter, or react native, it doesn't matter.

Or even worse, if web is just acceptable, then go web.