True. But it depends what everyone else does. You may be able to get ahead of some riders who stay on road bikes, where you can then get back in with them once you change back to the road bike and they catch you up, for example.
There will be multiple groups, right?
The time to change between bikes twice (if you do it quickly, and remember to use the Pairing screen to slam your brakes on so that you’re stopped and can do the change) will probably still be less than the time you gain on a lap of the jungle.
Each to their own, of course.