Decoupling running and type checking is quite popular nowadays, Vite does it as well. It can give a huge speed boost and allows you to ignore type errors while you're just messing around. Of course then you also need the discipline to eventually fix them, but there's probably a reason you went with TS instead of JS.
It is popular in newgen tooling but I feel its more a function of the slowness of `tsc` than anything else. I get why `tsc` is slow, and have a lot of respect for the team and the constraints they work under but I can't help but feeling if we were to get a faster type checker (potentially `stc` from the creator of `swc` which also does this? https://github.com/dudykr/stc), this choice would be less popular. However if I'm honest I don't know if TypeScript's type system means that there are some natural constraints on how fast it can be validated.