If you've played it long enough, you will want the ability to remove just a single sanc as opposed to the previous "reset" all. Anything that players find desirable for the purpose of making their toons more powerful, are candidates for Tynon to make money and therefore will cost gems. You need to understand that:

1) Each hero can only be sanctified up to a certain number of times

2) Each sanctification on a hero makes the next one LESS likely to succeed

These two reasons make removing a single sanc desirable.