Like Leer has 48 with a PP max I think. What's the point in that much? It's not like your going to use the move 48 times or something.
I think it's because if you're new to Pokemon you wouldn't know to go back and heal all the time, so to prevent newcomers from struggling (quite literally) they gave the moves a lot of PP so you could have more battles before healing.
Hope I was of assistance! -Salamaster