Let streamers contribute to their Community Challenges
Since streamers can't give channel points directly to their community, I think they should be able to contribute to their Community Challenges themselves.
That way, a streamer could reward a viewer (for instance after completing a minigame, like answering a trivia question) by donating points to the Community Challenge of their choosing. Since streamers have infinite channel points, this also allows them to complete a challenge early without refunding the points.
This should obviously be available only for the challenges that the streamer creates, not the ones provided by Twitch like the "Boost this stream" challenge.