My Audi A3 also got this hill hold assist button and sometime its great to use on slope and in traffic....here's more details i ve copied from audi forums n its similar in honda vezel i think
Hill Hold Assist is an optional extra and indefinitely holds the car when you come to a standstill. When active (there's a button next to the parking brake switch), every time you stop and firmly press the brake pedal it activates and shows a green handbrake light on the dash. This works particularly well in stop-start traffic, exiting busy motorway slip roads or approaching roundabouts. Just like the parking brake, it auto-releases when you move off again. A light touch of the brake pedal doesn't activate it, meaning you can creep out of junctions etc. if necessary.
It also automatically applies the full parking brake when you remove your seatbelt or switch off the ignition, with a red handbrake indicator lamp on the dash. In fact, it removes the need to use the parking brake switch entirely as it automates the whole process.*
When you re-start your car, it remembers the last setting meaning you don't have to re-activate it every time you drive off (if only stop-start would do the same!)