The use of fire-fighting hosereels for other uses does need a little care, as mentioned above in several replies. My concerns are particularly:
(a) the nozzle - liable to be dropped and otherwise misused. Either go for plastic nozzles which are cheap to replace (and keep spares in hand) or if to be used frequently consider a more substantial metal nozzle, preferably rubber-covered. But these latter are best not used on hosereels which are out of doors and which may be subject to vandalism or theft.
(b) train users to carefully rewind the hose evenly and tightly. If possible also to use an old cloth (or paper towels) held in the guiding hand to wipe/dry the surface as they rewind the hose.
If it is made clear to staff that such informal use is dependent on the correct use and tidying up after use then there should not be too much of a problem. The company will need to consider if they are willing to provide the metered water for such use, of course. There should also be safety training to remind potential users not to cause any hazards, for example the hose lying across a pathway, use in cold weather when water on the ground might freeze and never, of course, to direct the water onto another person. (Unless they are on fire.)
If the hosereel is in an external location it should be protected from the weather by some form of enclosure. This should include heating working on a frost thermostat to prevent freezing.
I think two hosereels working off the same main simultaneously will not be a problem. In any case if the second is in use for an emergency fire, then the user should have sounded the fire alarm; there is an expectation that the first hosereel user will immediately stop their non-fire use to do whatever the company's In Case of Fire instructions tell them to.