Come on, let's face it. There are times when you have a bunch of Gold and can't spend it because stuff is already upgrading. This spell isn't a permanent spell, It just let's you save Gold for 24 Hours or until needed.
I saw another forum for a spell like this, except a little different. This one, depending on how upgraded it was gives you a certain amount of re-spins. For example:
Level 1-5: 1 Free Re-spin
Level 6-10: 2 Free Re-spins
Level 11-15: 3 Free Re-spins
These can be spent over a period of time