Indeed this is the 'mother' of all IDX and CRM.
(Of course, it's just basic - so you may have to make it look beautiful.)
To best of my knowledge, many teams use this 'back-end', uses it for lead capture as well as lead follow up.
The follow up can be an auto-responder or even a text message.
It can integrate with any other database or CRM you are using.
There is a SOLO version and team version. Of course, team version is lot more expensive as compared to solo.
The BEST idx one can get.