Firstly, big big big thanks to everyone contributing to this. Massive, everyone of you (I’m not calling you fat).
In a two-way connection, between two devices (Windows and Android… not that it matters?)
Is there any reason anyone would setup folders on both devices as “Send Only” or both as “Receive Only”?
Is it useful for anything?
I tried it myself, I haven’t quite noticed a pattern, but I think the result is that each device is prompted of a change and is asked if they want to take action? Rather than automate the process, permission-free, it asks every time anything happens?
It might possibly be just a coincidence because I change the folders from Receive-Send to Receive-Receive/Send-Send/.
I don’t think it will have any useful effect, no. Each are best paired with at least one send-receive device on the other side. (One send-receive and multiple receive-only is fine, for example.)
It would be useful if you plan to come back later and add a third device sharing the same folder, but not setup as read only.
Suppose that this third device is often off line, and the other two devices that are read only hang around all the time hoping that the third device will show up on the network.
In addition I believe the two read only devices will both do local scans. So this is a good way to have them do the scans as a separate prestep when sharing. When the scans are done, you can see what has locally changed, and and perhaps fix scan errors, then decide to change the sharing mode for one or both folders.
Good answer, thanks chief.