Creating a SaaS service for Private Community Creators?

I was reading a post on reddit and what came to my mind was that for anyone who is in the process or have already created a private community for their subscribers, fans or what so ever. I could make an SaaS that would be integrated with a user tracking app that would track users who paid monthly, yearly etc.. and would collect the payment via payment processor integrated into the SaaS app.

I think this would be useful for people who are using sites like Discord, Slack, Facebook Groups and the like.

What do you guys think about this idea? Feedback is appreciated!