This idea has been merged into another idea. To comment or vote on this idea, please visit CF-I-169 Expand project donation types beyond Pledgie and PayPal..
The CurseForge website has a donate button on add-on pages which is not present in the Twitch client and users who do not visit the website might not be aware devs are accepting donations unless the devs had the foresight to include a donation link in the add-on description. IIUC you can only link to PayPal but some devs use Patreon/have Patreon links in the description - supporting more platforms might be another area to explore.
Thanks for the suggestion.
I've merged the Idea with 169 as they cover similar elements.
We will consider adding the donation buttons to the client, however this will not make it for the launch versions as we are now committed to a timeline.
You can read more about that in our roadmap board here