The charges limitation is a limitation, it stands so in the book, and not only is one of those limitation that you can disallow the players, it is so basic. And what does it do. Well, it removes the endurance cost of you power, it don't seems quite right to me.
Well ofc it limits the number of uses you have each day (or month, w-ever), but nulling the endurance cost seems more like an advantage to me.
Also there is another thing that makes no sense at all. You can apply adders to the charges limitation to make it into an advantage but not more than +1. but the no endurance cost is only a +1/2 advantage. How can charges be more usefull than no endurance cost?