We have an official game channel on Twitch -- we have tons of streamers that play the game, but (of course) most are variety streamers.

We'd love to autohost some of these folks playing our game, but it'd be awkward if we autohost them and they randomly play :any game that's not our game:. After all, it's the official game Twitch channel!

This would be useful to any themed streamers or gamers that only play x or y game. There may be variety streamers that play MOBAS but a LoL Twitch channel would autohost their friends only when they're playing that particular game.

Game name is already in the meta data, seems like it'd be minimal effort to implement!

There are times when I don't want to load in to a new stream after the one I was watching is over.

Some examples are when I am alt-tabbed and playing a game.

For me personally, while playing a game I will always experience a spike in bandwidth usage while the new hosted stream loads in.
Not all streams will use the same bitrate either, which is a concern, however I've not had issues with that problem so far.

Another example is when I am away from the computer, viewing twitch as it were actual TV.

Then inevitably having my ears blasted off by a hosted streamer with much higher audio settings.

I overall enjoy hosting as a feature, but there are times when it's not appropriate to have.
At least not now while stream-to-stream settings across twitch are not standardized in any way.