I don't think giving money is in the spirit of things, but children would prefer it. Gifts are better because it's not how much it's worth, but the thought that has gone in it. I hate it when people compare the value of the gifts exchanged, because it should be something personal that the person will like and enjoy. My brother gave me an expensive and useless photo album, that he told me cost over £100, where I would rather have just had a nice moleskine notebook that would have been more useful and thoughtful.
Generally gifts may be in various forms. They may in kind like pair of shoes, cell phones, cars or houses. As for cash gifts, they're usually initiated ny business establishments. In giving gifts therefore it depends on the occasion or the event.
In some situations the money is a better option. I usually give cash when a child is in a question, because in many occasions I don't know what is a child preference or what a child would love to have. You can pass gloriously or you can fail miserably. Cash is much better.