"Completely meaningless" and "in no way comparable?"

These statements are rather extreme and seem impossible to support. Energy output per mile with real world cycling has enormous variance as well. Why so much concern for precision regarding one and not the other?

I don't think there's much point in continuing here.

I'll continue with one last comment just for the sake of others who might be reading. The "distance" displayed on most stationary bikes is calculated by counting flywheel revolutions and multiplying by some arbitrary factor. It has no real correlation with the actual distance you would cover by pedaling a real bike with the same effort. It's a totally pointless number that tells you nothing useful about caloric expenditure, but some customers want to see it so the manufacturers put it on the display.

You can get an accurate calculation of real world cycling calories with a power meter. Everyone's cycling efficiency in terms of power output per calorie burned falls within a fairly narrow range so converting from time and watts to calories is simple. A good power meter accurate to within a couple percent can be added to any bike for about $700.

Smart trainers like a Tacx Neo or Wahoo Kickr also have accurate power meters built in. Those are substantially different from typical stationary bikes.

fwiw, I checked and the bike does have a power meter, I think it's an RS3 Lifecycle (or some similar model). I do a sustained 220-250w for an hour.

I understand the translation between power and mph is somewhat approximated, but I think you could be more generous. It's not unreasonable to make this kind of approximation and the numbers aren't meaningless.