Braking immediately cancels the gradual power decrease from the battery, allowing you to go straight into recharge/not deploying. As it only takes the tiniest flicker of braking to cause this, it does not lose you noticeable time. What this means is you can just deploy boost mode down most a straight, before deactivating it, dabbing the brakes, re-enabling straightline mode (Although there does seem to be tiny window of braking where you can bypass the ramp-down, and not de-activate straightline mode)
If you do all this quickly enough (which is not hard, with some practice) then there is potentially a not insignificant advantage to be gained from this exploit. May not be huge, but is still very likely to become the meta for this year's game, which would be a shame
