These women are called "Ring Girls" and have been part of the boxing folklore since 1965. The initial intent was to give the feeling of a show more than just a combat.
This article from livestrong.com says:
Ring Girl Duties
When it comes right down to it, the responsibilities of the ring girl aren't vast or complicated. Usually, the attractive ...
I believe the PRO WRESTLING LEAGUE-INDIA would satisfy the question; from their about page
THE Pro Wrestling League is a big leap in the history of oldest combat
sport. An initiative of ProSportify and Wrestling Federation of India,
PWL is the richest wrestling event ever. The league in the inaugural
year offers a prize purse of Rupees 15 crore ...
It's because the majority of watchers of UFC are men. Hence, the UFC uses those girls to get the attention of these men, which leads to a larger viewership and hence ultimately more money for the UFC.
It's the same concept that underlies cheerleaders in other American sports competitions. There's a slight difference in the sense that at least cheerleaders ...
This is the Olympic Schedule planning of RIO 2016.
As you can see there are also other sports like Weightlifting / Taekwondo / Shooting / Judo planned in a single day.
I think this is because of structure and techincal reason planning.