While in general this is a very interesting question (of almost philosophical quality, if I may add this), you will get a specific answer only if you go to the sub-forum of your specific Frequent Flyer Program.

Having said this, I would strongly recommend that you use your miles for travel and not for the wedding because the value of what you get for your miles is typically very bad if you do not use your miles for travel.

In any case, I wish you a great wedding.