Binder is honestly much better than D-Bus, but for various reasons I don't think we're going to see it much on desktop (though you can, in fact, use it there - and it originates from exactly such use).

The kdbus finally died when Linus sat down and proved that:

1) then-current userspace d-bus code was simply horrible

which led to kdbus being mainly about speed/latency, but...

2) Linus spent a weekend and got an userspace dbus server 80/20 solution that achieved better performance than kdbus

and

3) kdbus introduced no real new benefits that weren't ultimately triggered by "dbus is too slow", unlike Binder which involves fancy scheduling tricks to pass CPU quanta from one process to another along with RPC call.

Thus the final nail in coffin of kdbus (which was previously hampered by being considered too problematic to merge) was hammered in.