As I've said repeatedly, it's because something happens that's completely unrelated to what the action declared was. Add in that there's nothing the players can do do prevent this ahead of time. It's fine if it works for other games but just like I'm not going to ask if I land on Free Parking when playing D&D, I don't see the same process working for D&D. Sometimes there could easily be a negative consequence because you fail a stealth check and get noticed by the guards, fail an athletics check you fall and take damage, fail and animal handling and the dog becomes aggressive. Those things make sense to me but there's also no "success", just a "cost".