JLI have a more direct combat role, Pathfinders have a utlity role with their three deployable scanners.
My point exactly.
What else has a utility role? Engineer units.
How do they differ from mainline infantry? Much worse in combat, but has utility, costs much less and takes up much less pop.
How does Pathfinders differ from JLI? Worse in combat, but has utility in their beacons and...has utility in their beacons.
Of course the divide between Pathfinders and JLI in combat isn't precisely like that between engineer units and mainline infantry...but I'd also hardly say JLI's booby traps aren't utility as well.
I'd be happy using Pathfinders and their beacons with Paras if I had some goddamn pop with which to get Paras still while having Pathfinders. Of course, playing the Americans quickly consists of wishing you had pop in general.