High plat support main, and yea - it can work - but it has some big drawbacks. It's also not just Xin..
That's about every champion i've ever seen attempt a bot kill lane. The idea is that you combine CC with all-in burst potential. You'd want an ADC that can root and deal lots of damage. Draven and Jhin are pretty ideal.
You basically play together and blow the crap out of anyone who tries to trade with you. If you score a single kill, it can very quickly spiral out of control leading to an early pubstomp in bot lane.
With Runes Reforged, and Shield-happy supports, this strategy has pretty much completely fallen off, but you can still do it. It has lots of counters though - in addition to the shield meta, you also have lots of hard poke supports who can shut down all-in damage dealers pretty easily.
If you can't score a kill though, or you wind up losing lane, it turns out doubly as bad, as you essentially sacrifice a LOT of late game potential and mid game scaling. The support just isn't pulling in as much gold as a top lane, and that works out poorly for these champions come mid game.
