I'd been thinking that I preferred "sofa" behaving like "sofa 0", since I didn't want it burning turns if I forgot the argument, but I think precedents argue for it to be like "sofa 1".
- "use X" -> "use 1 X"
- "rest" -> "rest 1"
Just like the "sofa" command, the "rest" command will (usually) use turns to recover HP/MP. The comparison seems exact.