None of these offer extra perks. Patreon just allowed every channel to have tiers, which is a very nice change (unlike their new logo). Previously, it was a feature only available if you gave a higher cut to Patreon, I have always had it on the lowest cut.
They're obviously based on a low, middle and upper class Victoria 2 pop. They are just nice and cosmetic. Every Patreon supporter of every tier, or no tier, gets the same perks which are: Bonus clip videos, potential early access to main videos, special role on my Discord which in turn comes with its own nice perks.
Speaking of early access to videos: I was preparing for Bavaria Part 10 to have early access if it received limited monetisation on YouTube, but it didn't, so I published it as normal!