Under the units, a cable hanging out of the wall was never a good idea. If it was terminated in a flex outlet or an unswitched socket, that would be fine. In future you can use it for some other appliance if you want, such as a dishwasher, garbage gobbler, or another heater.
A few people complain about a socket on the grounds that the fuse in the plug is not easily accessible, but IME plug fuses blow approximately zero times per year so not really a concern.
A few people complain about a socket on the grounds that the fuse in the plug is not easily accessible, but IME plug fuses blow approximately zero times per year so not really a concern.