I just signed up to post another use case of unlimited mentions.
I’m a community moderator at the Fairphone Forum and we are planning a community trip to Amsterdam. In a group PM I’m composing a list of all the people who are going, differentiating if it’s unsure, or if they need accommodation.
My admin raised the limit to 15 mentions because I complained, but it’s still not enough. Generally speaking, I don’t see why moderators are limited in such a way. There is a reason they are mods, namely because the admins trust them.