To me, there are two types of weddings:
‘Our day’ types of wedding
‘Our marriage’ types of wedding
For the latter, people consider themselves and their guests because it is all about the celebration of them being joined together and sharing it with those they love. These weddings tend to be on a day that suits the majority of their guests. Depending on the age group, professions, number of guests etc.
For the former, this tends to be the dream day, and sometimes this means on a week day because that is the only way they can afford it, or abroad because that is the only way they can afford it, or because that is the only way they can get their ‘dream’ venue. But the focus is on the couple, their day and is not planned for the convenience of their guests.
I much prefer the ‘marriage’ type weddings.
Alternatively you have the "our marriage" types who don't particularly care about the day, just want to be married and focus on the actual marriage thus picking the cheapest / first day available.