It’s interesting how Google is catching up and allowing specific business models. For example, for a long time, Google has not allowed businesses with a login requirement to view product prices or a login requirement for purchasing an item.
8+ Years ago, I had a lot of clients, namely CCTV, where prices are not allowed to be shown by the manufacturer, resulting in these merchants only being allowed to offer a limited set of products and not the entire range.
Google is starting to catch up with these specific scenarios, albeit only for free listings (as of writing). This is excellent news.
The new policy means that if you now list products where you only allow pricing or product info to display upon logging in, this is currently allowed. Or even if you only allow registrations for the checkout process, this is now also allowed.
However, the catch! It’s only acceptable for free listings, not for shopping ads or Buy on Google, and you will be limited by performance. Low performance means you will get a lot less traffic.
Reference: https://support.google.com/merchants/answer/12285357