Taking your hand of at V1 ensures that you don't reject. It's a mental message. This manoeuvre requires predetermined action since there is no time to think. Keeping your hand there you are tempting yourself. On another day you may live to regret
Read the following accident report where because of the particular circumstances at the time, the pilot rejected the takeoff seconds after airborne. If he had elected to continue the take off, the fire was so severe that the aircraft would have surely crashed in flames.
ASN Aircraft accident British Aerospace BAe-748-378 Srs. 2B G-OJEM London-Stansted Airport (STN)
There may be one time in a pilot's career he may be forced to throw away the book and make an instant decision far removed from a company SOP.
That accident was one such case.
So it is a false premise to say dogmatically "Taking your hand off at V1 ensures that you don't reject."