For me running it (i.e. Being the "god", the narrrator etc.) is much more fun in such a context, as it's more about storytelling.
The main problem is that the game is quite unfun for the first 2-3 days: it's basically impossible to know who's who, so any sneeze, look or being the first one to speak will instantly make you a target of the crowd. There was a guy who just was a chatty guy and always started the conversation and he almost never made it past day 1. Absolutely unfair and unfun.
Whenever he wasn't killed on day 1 it was always due to someone standing up to the obvious unfairness and getting themselves killed, while he would get to live 1 extra night.
That's why we started adding extra unconventional roles and rules, to make up for this. For example, having a necromancer, who could turn a dead into a ghost who could do an action once. These changes would require to be more than 15 people, as you need to adjust the mafia in response.
The format is fun, the basic rules get boring pretty fast, given how newbies tend to play.
On the other hand, competitive mafia seems more about ninja communication and discussion, also I think they can also skip a voting.