When the chat is in "emote only" I wouldn't assume the streamer/mods to want anyone to type a message, this would defeat the whole purpose of the "emote only" mode. Even though you have to get this through channel points it could get spammy.

There's already a "workaround" on this if you're a Twitch partner, you get "permanent subscriptions" to give out to bots, etc. But I definitely think there should be an option for smaller streamers as well.