Anything can be sinful in excess. Anything at all.
I got married for a few thousand dollars. And this was a BASIC ceremony! My dress only cost $400-ish, and the tux rental was $150, my shoes were $20, rental of the chapel was $800 I think, Photographer we got at a STEAL for $500 (typically you spend well over $1000 if not a couple grand on this) the pastor was free (DH's grandfather), and the rest was reception/simple flowers, covered by my mum.
The only way we were able to keep costs THIS low? Was because we only had <20 people at the wedding.
After having gone through planning and executing a wedding? I can totally understand how people have $10,000 weddings or more. Because it is such a special day, and the pictures are important memories
So making it beautiful so you have those special memories? I understand how that can be important. And feeding/entertaining your guests? Obviously also important because some people travel SO far to be there, its nice to have something for them.
ANYTHING in excess though is sinful, so here is what I think:
If you have to go into debt to make your wedding happen? That is bad. There is NO reason to go into debt over a wedding. None whatsoever.
But if you can afford it? I really don't see a big deal, it's just a person's choice of what they want to remember the day like and what they want to see in those pictures (and how good they want those pictures to be
)