Why? Honestly, how can you "outsource" such a vital part of your web app to a third party? Not only is this a privacy disaster but also, if this user service goes down or has a temporary downtime, your own business is effectively unusable. I understand that it makes sense to not write these types of user functions and management things over and over again. The solution however, is not a SaaS, but a library or a littl…
One possible use case: Let's say you are building a new app and you don't know if it will be successful. At this point you are supposed to be working on the core. You are supposed to be talking with the users as soon as possible. You are not supposed to spend your time on things that don't matter such as registration, email delivery, forgot password. If the app becomes successful you can always implement these things…
Or you could, well, let's say, use a library or framework and spare you the work of integration too!