Originally Posted by Sardines

First of all, terminology is just marketing speak. A commuter bike has practical mounts for racks, while the geometry is more upright and stable. The bike manufacturers want you to have different bikes for different purposes. Any bike can be a "fitness" bike, since fitness is just aerobic/anaerobic training, and that's workload and heart rate. I ride for fitness and transport, and only use my drop bar road bike in group ride, and even then only when the groups which are so fast that aerodynamics come into play in keeping up with the group.
I do about 160-200 miles a week on my belt bike, for commute, fitness, errands etc. With a conventional chain drive train, I'd be servicing once every 1-1.5 weeks, which for me includes waxing the chain etc, which takes a minimum of 2 hours overall. All I do with my hub gates bikes is hit it with a medium pressure spray, brush and rinse. If it's heavily soiled, then I use a simple cleaner. All done in under 20 mins.

That's just the maintenance and ride. Your biggest issue will probably be the gearing and fit of the bike, considering you say you have a hilly ride around you. The Enviolo is a CVT, so as you shift, the change is progressive and smooth, unlike a gear change which tiered jumps in resistance. Moreover, unlike the rickety chain drivetrains, the belt drive is quieter! The limited 380% range means you either give up a little at the top or bottom end, depending on your ride, with the ability to change sprockets helps with choosing the range you want. The 380% range is the biggest limiting factor in the Enviolo system, but for most people, it's not important cos they don't need the top speed of a road bike.
Weight shouldn't matter much unless you have to carry your bike in buildings, cars or want to scurry up hills in the shortest time possible (which is antithetic to the purposes of commuting and even fitness). I would look at your ride data. If you don't constantly go pass 23mph, or hit 5% inclines much, the Enviolo system should suffice, and there is room for slight adjustment with sprockets. The low maintenance will pay back the premium in price in a few years from, the lubricants, chains etc. Good luck.