Host the Auth Service on an Independent/Separate Domain?

At present we have the Auth Service deployed to Heroku: https://dwylauth.herokuapp.com
This is fine for MVP as it's _free_ and has reasonable service quality.
I was originally thinking of running the Auth service as a subdomain of dwyl, specifically https://auth.dwyl.com (this is still my plan in the short term; after MVP), but what if we **think _bigger_**?

What are your thoughts on running the Auth App on a completely separate domain and making it available as a service to _any_ developer/project? e.g: https://domainr.com/autha.co?q=autha

The advantage would be clear: **Feedback** and ***contributions*** from developers who would use the "Auth" product. Having a _separate_ project would make it clear to _anyone_ that the Auth Service is decoupled/independent from dwyl.com and can be used in _any_ project. By _encouraging_ people to use it in _any_ project people will be more likely to request features/improvements and crucially they will _contribute_ them! I _hypothesise_ that having the auth service on [auth.dwyl.com](https://auth.dwyl.com) will mean it remains in relative obscurity which means we will receive fewer contributions. Why do contributions even _matter_? "Free" security updates and improvements that _everyone_ benefits from!

The disadvantage is an extra $20/year of cost for the domain, time to build a nice landing page and time to maintain the project.

Thoughts?