What's the best argument you've used to get a friend on board with BTC? My friend is getting close, but still thinks BTC is a fad...
Tell your friend that if Bitcoin is a fad, it's the all-time longest running fad that's been going on 15 years. Nevertheless, your friend will eventually realize that Bitcoin is not a fad and he will either not be able to afford Bitcoin, or he will end up buying it "at the price that he deserves."