Technically speaking, Blue 2-1 is not strictly an on/off switch because the dimmer module cannot be bypassed and it doesn’t output 100% sine-wave power. [1] Given it’s inappropriate to wire a dimmer to wall outlet, I think it’s also inappropriate to wire blue 2-1 to an outlet.
Anyway, even for real on/off switches (e.g caseta on/off switches), they typically don’t allow connecting to outlets.