One can't really charge a battery with power spikes from randomly hitting the brakes. Only part of the braking energy is recoverable, for example when braking to reduce speed while descending a long slope. Braking strategy should also be different in this case: similar to engine braking in regular vehicles. Since most EVs rarely have a multi speed gearbox, regenerative braking should be built into the brake pedal.

In practice it works fine on all EVs I driven. Doesn't take much getting used to.

I'd wager there are far more fossil fuel vehicles on the road with regenerative braking than there are EVs.

Intrigued, how would that work?

I think OP is referring to hybrid ICE vehicles.

Not very much when you are on the freeway.

I guess if you never ever use brakes it has no advantage.