Make a global loyalty points reward for subscribing / gifting / etc
I suggest there be created a "Global" Loyalty points system in addition to channel-specific points; each Twitch user would have a global "Twitch loyalty points" point balance.
Subscribing to a channel, Gifting to a channel, or spending a certain amount of time watching the in-video ads inserted by Twitch would be actions that each reward the viewer with a certain number of Twitch points Per Subscription, or Gift Sub, etc.
Finally, if the user has gifted enough subs, or subscribed to a large enough number of channels: the global Twitch loyalty points should be redeemable for various rewards - which are global in nature and not channel-specific, for example:
"unlock an exclusive emote", "1 free sub for 24 hours", "global ad-free viewing for X hours", etc