Obviously i know they can be stored / shared on a file server or in the document store on Royal Server but it would be nice to have the option
Well, storing the data on SQL is not as straight forward because internally we don't store the data in a way to make it easy for SQL storage. A completely new data access layer has to be implemented to make this possible. Anyway, Royal Server for team environments is not mandatory. You can still store it on a file share and let multiple users sync their changes.
Would save on the cost of buying Royal Server in a team environment, it would also be possible to do SQL Log shipping for a DR scenario without having to make sure a file is backed up and stored someone central in two different locations
there are no plans to store a document in a SQL db. I'm curious, what benefits do you see storing documents in a SQL db?