If you're good enough to be conservative in what you pull in, you'll still be that, except you get to benefit from all the things a compilation step can offer. It still strikes me as a somewhat arbitrary limitation to impose on yourself.
I use webpack for almost all my projects, and TypeScript for a bunch of them. I'm also very mindful of what packages I use and the result is nice little bundle. I wouldn't be able to get the results I want if I limited myself by not having a compilation step.
(I know full well why they want people to the install the app, but I still find it unfortunate that they a) don't remember that I dismiss it/have an option to never ask me and b) despite the redesign and having a relatively good mobile experience (assuming you didn't first hit an `amp.` link) still push the app.
Look at a single post on the new React based Reddit. I just did and got 65 http requests loading 1.6MB of data.
It's almost everywhere like that these days. Too much tools. Too little concern for the actual outcome.