other than to do a stoppie, it seems pointless. but I‘ve never been a hardcore biker.
It's there to stop the bike. When you stop hard the weight shifts to the front so most of the weight ends up on the front wheel. Did you notice the brakes are bigger on front or on some bikes you have 2 discs on front and one on back. During a hard stop about 80% of the braking is done by the front wheel. You would never be able to make a fast stop with out a front brake.
No, the rear brake is NOT the primary brake on a motorcycle (or a car for that matter). The FRONT brake does MOST of the braking on a bike, especially a sport bike where all of the braking will be once weight transfer unweights the rear of the bike. Rear brakes on bikes are relatively weak to keep you from skidding the rear tire. You should use BOTH brakes in proportion to your need to stop. Initially using more rear and progressively adding more front brake in and easing off the rear brake as yours and the bike's weight shifts to the front wheel. You modulate the brakes to keep the wheels from skidding. Maximum braking force is applied when you reach that point just before the front wheel starts to skid.
on a motorcycle, 70% of your stopping power is in the front brakes.when you decelerate, the bike pitches forward, taking even more weight off the rear wheel. So, the point is to get the bike to safely stop in the least amount of distance.
