Unless you're cycling across thousands of miles of Siberian tundra, or you're one of those waiting-for-death geezers who have lost all interest in the world, you're going to want to take an occasional day off to be a tourist whenever you get to an interesting city, relic site, national park, or other such attraction. You spent all that effort to get there on a bicycle. You're not going to just ride past without stopping, right?
That said, I've met multiple such geezers on the road who never stop for attractions. Tragic when one gets to the age where all curiosity toward the world is dead. Kudos to them for still being able to cycle at least. The brain is just as important as the body...
In the light of this, I'll clarify my feelings about rest days.
I am inclined to make a distinction between days taken off to do stuff and rest days. Days sitting in camp or a motel room all day resting is not something I'd do unless sick or something and yet I see folks choosing to do that. Even at home I don't tend to take days off. It has been about 6 months since I have missed my morning mtb ride.
As far as recovery... I think an easy ride is better recovery than no ride.
Also you can do a lot of tourist stuff and still ride part of the day. Hiking to a waterfall, visiting a museum or other attraction, chatting up the local folks, or whatever will usually still allow for riding down the road a ways to another campsite.