Got this response from Insync
So sorry for the confusion. The intended behaviour (auto-syncing new files) was not yet implemented in Insync 3, but we have spoken to our developers and they are going to fix this in the later builds. It will behave like it did on 1.x wherein new files will auto-sync after it’s added on Drive.
Unbelievable. I don’t know what they think they are building as it seems to run counter to what I would expect.