In principle you’ll still be able to use all of the features that existed before this flag but you’ll need to compile the code if targeting Node.js. I do think that this new flag is going to draw people away and we’ll probably see a bunch of tsconfig presets and boilerplate projects setting it to true.

If you’re using a bundler then your’re not to going benefit from it in the medium term. It’s possible this will unlock faster build times with them in the future.