Seems like a willpower issue if you're using it to scum encounters, not to mention infinitely more immersion breaking than the option simply existing. But I see no reason why not forbid it on higher difficulties as a challenge, I guess?
But overall I think the system is great as it is because you can use it to fix mistakes that you need the first few hours of act 1 to learn, in terms of ability score tinkering and stuff "Oh I made all my stats odd numbers and now I know that's not really what I should be doing". Or in some cases being like "I actually don't enjoy this class so I'm going to switch to something more my speed, but I'm not interested in starting over."
Though, having gone through this as a Paladin who found he didn't like oathbreaker abilities, it is weird that restoring your oath is basically just a respec that costs 1000g, while everyone else only has to pay 100g.
I get it but it is weird.
