at this point the question should be: who the hell still isn't supporting BU?
The only people who matter, the Core devs, aren't supporting BU.
If the Core devs don't support BU, who is going to fix it when they break something (again)?
And who will import all the nifty new features from Core to BU?
It's like buying a new car and installing a bunch of
homespun, amateur "custom" electrical work to support your shitty try-hard stereo/subs/lights.
When you eventually break the basic functionality for the sake of your gimmicks, the dealer is going to laugh in your face when you try to get it fixed under warranty.