At first glance, this is interesting software for anyone who wants to present and sell self-created content in an appealing way.
The website Builder works well and looks good. GDPR-Compliance is ok, it is a UK Product, and Users that register on your SupaPass Website even have the ability to delete their own accounts. Also, you can translate website content (including buttons etc.) in your own language. So far so good.

But...
Let's say I want to present or sell some Videos. Unfortunately, this is where the limitations begin. The only possibility I have with AppSumo Deal is to import Youtube Videos. (And no: I cannot embed Videos hosted elsewhere. For that I would need the possibility to create Articles on SupaPass, which is only included with Growth Plan – see below.)
Importing of Youtube Videos is rather complicated. To import a YT Video, you have to go to Integrations Tab, click "Create new Video" and then insert YT Video ID and choose Access Level for this Video (e.g. free, only with membership etc.) It seems that you have to set up every single YT Video like this. I think the word "import" doesn't quite get it. It's hard work ;)
While unlisted YT videos can be used (what is good so far), the link to the original YT video can be obtained inside SupaPass with ease, because YT surface is not masked. Therefore there is no protection against sharing the video link with others in order to bypass the paywall.
Another problem: if you want, you can import any YT content that others have created into your SupaPass website and then sell it as your own content. Legally, this is pretty shady.

Overall: The Website Builder looks good, but the Software in my opinion only really makes sense when it includes the possibility to upload your very own content (Videos, Audio) and to create articles directly in the Website (instead of importing article feeds from your Wordpress-Blog). But in order to get these features, you have to upgrade to Growth Plan. So I'm afraid: this will be a refund.