Of course, the other practical use of rear (trail) braking in a curve is to shave off some speed safely, say in the case of an unexpected decreasing radius curve, but never using the front brake, unless you have learned to feather it so lightly that you won't give up your front tire traction in that curve.
Over the years I learned to slightly advance on the rear brake, use the CG shift and then go on the front lever.
And just for that ability to actually use them
while leaned, I prefer them standard, non-ABS brakes so much.
Their so precise, so sensitive, providing such a direct connection to the tire patch on the road, its simply amazing... enables me to to use both brakes into the entrance/1st third of a turn, release the front before the vertex, maintaining only trail brake through there, to seamlessly change to "max power" once past it.
And I also love them over that sensible "analogue" feeling and feedback, one can use/apply them so gently, use the rear brake for speed control in the tight corner, thus "pre-loading" the tranny line, so there is no slag, no "turtle kiss" during the change from deceleration to acceleration, the bike's suspension stays levelled, no "bounce" from sudden load changes... kinda like flying
That would be one of the times when I did use the rear brake, but in reality I was never in that situation anyway, so purely theoretical at this point.
Them instructors always tease the attendees there...
There is a track with a marker + cones where you've to start your brake practice, with an electronic metering device, logging your approach speed and stopping distance.
Any then it starts:
- use front brake only! Runs with 30mph, 45, 50... (depending on the skill level of the group...)
then:
- now rear brake only! Again with 30, 45... (uhhh, at first you see a lot of skidding and blue smoke there ;-) . Its repeated till all have learned how to use the rear brake only without locking it up)
Finally:
- now both brakes, aways! Again starting slow at 30mph approach, once the folks get the hang of not over-breaking the rear, they increase to 45, 50 and beyond...
Coming in hot with 60 or 75mph after a few runs is common and they log your gained best stopping distance...
Sure, controlled conditions, dry road, abrasive tarmac... the goal of this practice is to learn and memorize your ideal pressure points (and experience what your brakes can
really do), and loose the fear of reaching into them binders; over fear of going down many are just too gentle on the brakes and need to overcome that mental barrier...
In regular road use one would hardly come near of 100% capacity on the front brake, road surface never perfect, etc... so assistance of rear brake has to be "automated"...
And none of us is a 100th percentile rider, there is always headroom to learn and improve... daily, every mile we go...