I remember a similar argument against Visual SourceSafe[0].
We had been using SS since it was done by OneTree (borged by MS).
MS used an internal tool, instead.
VSS did do one cool trick, which I have yet to see replicated elsewhere: You could construct "artificial workspaces," composed of elements (down to individual files) in other workspaces, so, when you checked out (it was all checkout/checkin, back then), you actually checked out from (and back into) the original workspace.
We had been using SS since it was done by OneTree (borged by MS).
MS used an internal tool, instead.
VSS did do one cool trick, which I have yet to see replicated elsewhere: You could construct "artificial workspaces," composed of elements (down to individual files) in other workspaces, so, when you checked out (it was all checkout/checkin, back then), you actually checked out from (and back into) the original workspace.
[0] https://en.wikipedia.org/wiki/Microsoft_Visual_SourceSafe