That feature is for JS files. It helps you convert your JS project into flow/TS in a piecewise manner. Otherwise you'll have to do a major rewrite in a very short amount of time.
> Otherwise you'll have to do a major rewrite in a very short amount of time.
This just isn't true. TS was designed from the beginning to allow gradually adding types. Whether transpiling or using comments, you can change one file at a time.
