It makes good sense.
The cycle path doesn't have to carry the weight of a road, meaning it's a whole lot cheaper to build and maintain.  And perambulators, wheelchairs, and mobility scooters don't do well with graveled paths.  And having had to use a cane for a few years, those don't either.
It's also entirely possible that the bike path and the roadway might share the same right-of-way, but be authorized and funded by different government polities, like city vs. county, or even different agencies within the same polity.  The area I do most of my riding is like that.