-bin seems like a strange thing when you are doing Gentoo, which is all about compile locally. Gentoo has always been about choice and -bin is a choice. However you lose USE flag choice decision with a -bin.
The possible combinations that Gentoo allows looks to me like a sort of Linux immune system in action. Quite a few "unpopular" flags will get used (lol USEd) somewhere by someone that will be more motivated on average to log a bug somewhere.
Gentoo also got the console shell look (colours, fonts etc) right way before any other distro. It's copied widely.
Sure, binary packages don't reduce choice though since they are available in addition to the normal packages (except for stuff that is not open source at all).
Wanting to have control over config via use flags for your system doesn't mean that there aren't packages were you don't really need that. Like if you only use Libre Office a couple times per year on your aging laptop, do you really care enough about the exact USE config to justify compiling it yourself? Even more so if you need it on short notice. Or if you only use Chromium/whatever to check that your website works with that browser but don't actually use it yourself, why bother compiling it.
IIRC there used to be a Gentoo fork (forgot the name) that extended this concept to all packages, so if you used default USE flags you did not need to compile things yourself.
The possible combinations that Gentoo allows looks to me like a sort of Linux immune system in action. Quite a few "unpopular" flags will get used (lol USEd) somewhere by someone that will be more motivated on average to log a bug somewhere.
Gentoo also got the console shell look (colours, fonts etc) right way before any other distro. It's copied widely.