I think it’s cool in concept, and very interesting to see how the Membership block develops.
In talking with Jeremy, I was specific to ask two things about the “Membership Block”:
On one hand it does say “Membership” which, for some people would imply that they are in-the-act-of “joining something”.
At the same time, the block takes recurring payments as well implying that there would be a “subscription” element.

…..yet the new “Membership Block” doesn’t actually DO anything. In other words, there’s no restricting of content for premium subscribers, no downloading of something premium, or any other type of “function”.

https://prnt.sc/nqepkl

I do like the fact that it connects with Stripe and avoids PayPal. While that might not be preferred by some people, most are growing tired of PayPal shenanigans.

For the first round of beta, the “Membership Block” basically could be compared to a Patreon effect or the Donate Button that people see in the .org/plugin area.

I do like where the “Membership Block” might/could be headed:

This is still something we are trying to figure out. We are actively working on the feature and will make more changes to it before it is available to all Jetpack site owners. We are collecting feedback from WordPress.com and Jetpack Beta testers like you (thank you!) to better understand the expectations folks have from that feature, and the options they’d like to see.

At first, it may only be a payment button, just like the one you are seeing today when you add the current Beta block to one of your posts. If folks want more, we’ll see how that can be done. We’re definitely considering adding content restriction to the mix; we will need to decide if we can reasonably implement it to the current button as it is, or if that should be done in a different block leveraging the same API for example.

As I was testing the block out, that was Jeremy’s reply which sounds like there is plenty of room to grow with the “Membership Block”