Is it ok to use your child's birthday gift money?

If your young child (say no older than 5) gets cash for their birthday, is it okay to take that money and use it toward something related to their birthday? Maybe a party or large gift that you know the child wants or would like, but you could not afford without using that money?

The rationale is that s/he is too young to really know how to spend that money wisely and that the money is still going toward the child’s birthday celebration.

The other thought is that the money belongs to the child and it should be given to them to do as they please or should be saved for them.