Stupid question – holiday resources

Crystal, Emerald, Amber, iron, obviously these things I figured out are used to upgrade things like the Christmas tree, etc.… Is there any reason not to just literally spend them as quick as possible in their entirety? Am I missing a bigger picture here? Like obviously as you upgrade things you get rewards. is there a strategy to apply these or?

I don’t know if it’s just a simple as apply Every resource you have to as many things as you can to get as many rewards as you can.