Marriage

So, as the title suggests, it is controversial, but in a different way. Tell me if I need to post this elsewhere!

My family does not agree with my opinion and I really want to know other people's...

Does it make sense for a couple that does not believe in any religion to marry in a church? F.e. my cousin is atheist, so is his wife, but they are still getting married in a church with a traditional Christian Service to please my relatives.

Wouldn't they rather want to marry legally? With a beautiful wedding around it?

Genuinely curious!