Almost every vehicle, motorized or not, that I've ever driven can lock up the tires. For a vehicle used for commuting or other non-performance applications that's basically all that matters. If you can outbrake your tires (or in the case of a short + high-CG vehicle like a bike, outbrake your ability to keep the thing from flipping over the front wheel) any more braking ability is irrelevant.
For those sorts of uses where a single panic stop is the hardest the brakes will ever work it's basically binary, you either have enough brakes or you don't, and once you have enough adding more doesn't gain you anything.
Performance applications where you're constantly hard on the brakes, off, then back on like a car on a race track are where the scale becomes analog. Larger brakes that are better at dissipating heat will last longer before fading out, and if good enough will not fade during the expected race session.
tl;dr: Unless you're on a race track or similar there's only "enough brakes" or "not enough brakes" and no reason to go better.