I'm looking for information that clearly describes the difference between a custom domain created through Azure Active Directory (AAD) and a custom domain created through App Service Domains.
It makes sense that an App Service domain is bought specifically for use with App Services, but why can't this same domain not be used for other purposes? (eg. nginx proxy running on VM)
The custom domain bought via AAD is more generic and doesn't imply it's for App Services only.
I'm asking because it's a lot simpler and faster to get started with an App Service Domain, since we don't need a global administrator to create a custom domain via AAD.
Thank you.
There is no difference. If you buy an app service domain, it's a domain like any other domain. In Azure it's just called 'app service domain', but you can use it for other purposes as well, not just app services.