see Making extremely powerful mundane combatants? - #13 by Tugdual
IC is pointless because you can have Char+2 from the 7 free points. A fighter can have 2,1,1,1 on the 4 physical char and Per+1. Once you get there, IC only gives you an extra +1.
As for the "can't buy", you are just demonstrating the opposite: not only does it save you xp, but it also allows you to exceed the age limit.
- Fine, keep the age limit and get MT 5: 3+2 "allowed you to put" 45xp "elsewhere".
- Or look 30 years after Gauntlet: MoH Ranulf+30 "allowed him to put" 85 xp "elsewhere".
{Which means Ranulf saved 45 xp at Gauntlet and another 40 xp later, almost 3 years of Later Life}
The only way to say "Puissant is bad" is to pick a Char+0 along with an Ability 3, aka something you are unwilling to use.