Probably the single biggest thing in my own experience - and that the SPA naysayers or php/flask/ruby commenters miss, the ability to work on front end while the browser updates automatically, without a full page reload, and while maintaining state (for example, complex form fills), including layout/style changes (which are automatically scoped and vendor prefixed for you) is the single greatest time saver and ergonomic feature that at least for me, makes React + webpack + all the things they’re complaining about worth it over any caveats and/or benefits of “X instead.”