The use of fans is disappointing; that means it can't go outside. My first thought when seeing it is that it'd be great for doing external inspections, and could even have its own private little airlock to get in and out.
Maybe they could make a version with ionic thrusters, that stays outside all of the time. It could have a 'nest' where it parks and refuels when not in use.
Ion thrusters have tiny acceleration, which is why they're best on deep space missions (slow and steady wins the race). I wouldn't think they'd be practical for this type of thing, which you'd want to go one or a few kilometers per hour over distances of tens of meters.
I'm sure there are very strict rules about having anything flammable or explosive on board ISS, which pretty much means you can't have a drone that can move under its on propulsion both inside and outside the station.
NASA's Manned Maneuvering Units used compressed nitrogen. But I'm not sure there'd be a huge benefit to having indoor/outdoor capabilities in a single drone. You'd have to cycle the airlock every time it went in or out, and it would be bulkier and less efficient in either mode than a dedicated unit.
Easier to start inside, where you can pick it up if it runs out of batteries or glitches out. Less chance of poking a hole in something critical, as well.
Or maybe not whole rails, but just fixtures the drone could grab onto. You could supply the drone with power and control signals through the fixtures, and the drone could kinda travel everywhere by just grabbing onto a nearby fixture, then releasing the previous one. Wouldn't that be great? /s
Maybe they could make a version with ionic thrusters, that stays outside all of the time. It could have a 'nest' where it parks and refuels when not in use.