But the Rich Boy isn't in the post game, he's on an early route with a Level 8 Zigzagoon. A normal Potion or at most a Super Potion would heal it to full HP. Now to be fair a Full Restore also cures any status condition... but I seriously doubt anyone would use a status inflicting move on it. :P Maybe later in the game when you re-challenge him and it has evolved (and post game he gets a male Pyroar), but at the start? Actually he should technically not be able to buy Full Restores, I question whether he has any badges. :P
During the main story I always give out a small "yeah!" whenever I find a vending machine or later on when I find the Moomoo Milk/Ailment curing item. Honestly the standard potion items are kind of outclassed. Sure you can buy them in bulk unlike the vending machine, but that's just for convenience and honestly something that could easily be changed. You know what, I think they should get rid of the status ailment curing items and just have the Potion, Super Potion, and Hyper Potion also cure status ailments. That way it gives them back a purpose, you can either use a plain old water, soda, or lemonade to heal some HP OR you can use a Potion which heals some HP AND cures status ailments. Heck, if they did that I'd even suggest selling the drinks in the marts as they'd now be doing different functions.