What a lot of fuss about a wedding, just about the most over-rated event on this planet.
Since childhood I have been bemused by this need to dress up, have huge parties and, in many cases spend ridiculous sums of money, to mark a relationship that, as we know, is so often a total failure.
My own dream was always a wedding like that chosen by the OP's daughter. However first time around I did agree for DH's sake, as much as anything to have 20 close family present, but kept the rest of the event is simple as possible.
I always vowed that next time I got married that i would do what the OP's daughter plans - except that 56 years on, I am still married to Husband No 1.
My own daughter, with views similar to mine chose to skip the whole thing. She decided when quite young that she preferred to be single, uncommitted and childless - and she has done just that, so saved us any problems with weddings.
The events to celebrate are the ones that show the marriage was a serious event and the couple of staying power. 10, 25, 50 year anniversaries are worth pushing the boat out for, and entertaining family and friends, but its initiation is best kept as low key as possible.
I do appreciate how upset the OP is and at a personal level, I sympathise with her devastation. But more generally, as far as I am concerned the more weddings like this one the better.