I have mainly been using the rotary encoder for volume, yes. I have to say it does _feel_ very nice though, much more satisfying than changing volume with vol up/down media keys.

I tested out using the encoder for other things like zoom in/out but I haven't found anything where it felt more useful than volume.

In regards to the case, the aluminium case gives the device a reassuring heft. My preference would be to make it out of some % of recycled aluminium but this is proving hard to source in low volumes.