You're right the tooling could be better and that TS trips up beginners. Promises trip up beginners as well though but that doesn't mean they're not standard.
TS is very, very close to being standard practice. It's already being used by over 50% of JS developers [0]. It doesn't have to be beginner/tooling friendly to be widespread.
I never said it was standard. I said it's very, very close. 50% (actually 58.5% of just those that would use it again) is certainly within the realm of critical mass.
