Is claiming childcare expenses only beneficial if you are going to owe on your taxes?

Legs asked: For instance.. without claiming it, if someone were to get $300 back would it increase that amount to claim the childcare expenses? Or would it only benefit a person who was going to owe taxes?
I hope that makes sense..
Thanks.

Can I deduct more of my childcare expenses as a corporation?

2tally Clueless asked:
My wife is a freelance consultant. In order for her to work we have to pay for childcare for my son. I know I can deduct a small amount of childcare from my personal taxes. If my wife incorporated, would we be able to deduct more childcare as a necessary business expense?
I know [...]