Compared to 11, 19, or even 4, yes, they are terrible XP per recruit.
But they are much better in XP/day, since they run faster.
So If I can keep TC11 running but build up surplus recruits over time, spending them to get more feeder heroes makes sense to me. (After keeping TC11x3 full)
Currently I’m using all my recruits, all my rugged clothes, all my backpacks, and am working down through my surplus of swords.