The TL;DR on this one is "if someone wants to quit being addicted to nicotine a vape is a decent way to stop." If they don't want to, they'll just switch to the vape instead of smoking.
So they have to want to quit in order to get any benefit.
This is absolutely true, the hardest part of quitting smoking has never been getting rid of the nicotine addiction. It's not starting again the next time you're at a bar and your friend goes outside for a smoke and offers you one.