No
Extensions may not transact or encourage the transacting of monetary exchange in relation to any non-Twitch/Amazon commerce instruments.
Basically you can charge streamers access to your Extension and/or features (in the future) but there won’t be a way to make/allow users to spend money in your extension. Since anything you would build is a competing product to Subscriptions or Cheering.
What you can do is say “hey you should buy bits”
So basically you can’t use an extension to suggest people go to paypal/etc to Tip/Donate either too
Of course this is my interpretation of what the guidelines say, and I stand to be corrected