Tbh I always forget about this ability, i'll try use that aswell.
What is in general better in USF vs Ost? Like you also mentioned, just rushing capt, but does this mean LT is never really used anymore in the current meta against both Ost and OKW?
Riflemen are awesome vs grens in general. just get them close so they can rip them apart with m1 garands' superior fire rate. I literally never (and i do mean NEVER) tech leutenant. In pro games, its viable because both players like to scale evenly, but in regular matchmaking i find LT useless. The reason, at least for me, is that it means you have no AT if your opponent rushes armor. You can always get the bazooka upgrade, but
1. bazookas are still pretty bad
2. you are then paying more fuel and MP into tech than you would have going for captain.
LT just delays teching and doesn't seem worth it for the crappy .50 cals and early game vehicles. It pushed the already large USF early-game advantage, but it leaves you even more vulnerable in the late game, where USF is already weak. Captain early on is a pretty good unit if you either keep him hidden in case of 222 rush or use him to flank and do decent cqc damage with the one thompson member.
My build order goes rifle, rifle, rifle, (additional rifle if you dont have good fuel income to get CPT), captain, ambulance, pak howie, AT gun (if needed). Then it varies depending on which commander I choose.