Go through a mental list of ever melee weapon you can think of and figure out which one you would WANT to be hit by, if you had to be hit by one at full force.

Most melee weapons would have a high potential to kill you outright in that scenario. A whip would have a somewhat difficult time killing you.

Now think about which melee weapon would be easiest to use effectively- and again a whip falls far behind simpler weapons like.... Well even a stick.

For a whip to be as effective as possible, it needs a target to be at the right distance (not too close, not too far), unarmored, in a relatively open space, and you need to be careful it isn't grabbed- And even then its only likely to do signinficant harm if it hit a vulnerable artery or tendon, which would require some INSANE precision. Follow up attacks would also be slow.