Are you referring to some sort of asset marketplace with in-app purchases, or something like that? If so, I've never used it. I can say that you don't need to be logged in to use Affinity Photo, Designer, or Publisher: I don't even have an Affinity account, let alone do I need to log in to use the software. My recollection of buying their products is: you pay them over the web, they send an email with an activation code, you paste the code into the app, and that's it.