My wife and I got married in England. So it was a "destination wedding" for American friends and family, and "just a train ride" for British friends and family.
I've been to a ton of weddings. Most of the time the bride and groom spent stupid amounts of money trying to make something memorable, when it's always just going to be a big mob of people, a pretty dress, booze and some expensive cake. I mean, you can put a $500 ice sculpture in the middle, but it doesn't change anything really.
But having a wedding in a unique location can really have an impact. Ours was in a small church 300 years older than the United States. It sticks out to me. And when it was all done, the whole event was under $6k for me and the wife. So cheap.
I'd recommend the destination wedding thing to anybody like me who doesn't give a crap if more than 10-50 people they know come and just wants a special day in a cool place with his bride.
And I think any person receiving an invitation, be they friends or family, should immediately ask themselves, "Would I be happy to vacation there anyway at that time and for that cost?" If the answer is no, there should be no obligation to go.