It would be interesting to have in-game. I feel like it would answer a very specific use on the server, thus I don't think it should be implemented as an emotes pack, but more into an actual feature, if anything, where you can do something along the lines of "RainTM invited you to a Flying minigame. Click here to join the queue.". It could even be introduced as a party feature. For example, if the party leader joins a minigame queue, everyone in the said-party automagically joins it too (maybe it even already works that way).
That said, while it would be fun (either as emotes or as a feature), I still feel like it might not be really needed at the moment since a simple message along with the players then joining the queue is actually faster. If the staff members were to follow the emotes "path", this suggestion should, in my opinion, be added into the "base game", so that it simply becomes a new feature everyone has access to, without the need to purchase it.