Well Tweetbot will be paying Twitter $11/mo. For them to also make some money, they have to charge you closer to $20/mo.
Tweetbot will not pay that, they'll poll instead of stream and have a worse product because of it.
Re:Premium Account Activity API
by kylehotchkiss on Wednesday May 16, 2018 @03:08PM
(#17085467)
Tweetbot with poll still beats Twitter.com with streaming.
I'd pay $10/month for Tweetbot. It is an ad-free twitter experience after all.