In Divinity, earning enough experience to get to level 38, Wisdom would give you an extra level. Earning enough to reach level 65 would result in 2 extra levels. While possible, I don't think very many people got that high without cheating or running to a bug with experience bombs.
In Beyond Divinity, each level gives you a 1% bonus, but only for the character who knows the skill. You would need 4 times the skill points to achieve the same result as in Divinity. However, I've seen someone mention being at level 30 at the end of the game, so if this is common, even 20 skill points are not going to give you an extra level, merely let you level a little faster.
If you have spare skill points and lots of gold, you can put them in Wisdom until you have a better use, then unlearn it.