And here comes the main question, what are exact benifits of having them for Ostheer not counting faust? Why whould you need inf which is inferior vs both tommies\rifles early and requare MG support or 2vs1 ratio and later on they become a liability requaring constant babysitting and only giving you constant MP bleed when they are outside of cover.
And outside of early LMG advantage, later on they wont have any advantage over Tommies\Rifles.
Not to mention, that having them forcing Ost into investing more into direct AI, so it is actually what is more cost effective 1 280 squad or 1 240 squad which requares another 240+mp unit supporting it.
This is exact reason why ppl avoiding grenadiers outside of VSL. Investing into grenadiers in a long run just puts you into a disadvantage, always.
Well, speaking from 3v3 experience in rank level 16-19 I usually see ostruppen being used as flank covers and first infantry before the tank push. Give them an LMG and they can hold in cover quite well. If you go ostruppen, not only are you getting a good faust on a cheap, easy to reinforce unit, but you are also saving up space for the late game tanks to win the game. I've never ever seen good players play ostruppen against me by taking them late game and blobbing them against me. To be honest, not only is it cancerous to play against them on most of the maps where there is good early cover around crucial points, but they also pay themselves later on as a complete support unit that lives in the crates made by the stukas or werfers of lefhs.
Is it true that the stats on them are poor? Yes
Are they cheap (+ reinforce)? Also yes.
If you play ostruppen, late game you're not counting on them to do the heavy lifting but pgrens and tanks. I've seldom seen good players under-utilize Osttruppen. They are a complete niche unit that good players will know how to maximize the effect from early to late.
They are not meant to have an advantage over tommies. Why would they? Are you saying that every unit needs to stand up to every other? Ostt are dirt cheap. They should never ever be able to counter upgraded mainline from USF or UKF.
If you can't accept that then no matter what I say will change your mind so I'll leave it at that.
EDIT: To reply to the gren disadvantage sentence. Grens cost 240 and their purpose is to hold the line, not charge in. You charge in with them once you know there are no close range dangers. Vet3 grens with LMGs mow down all infantry when they are behind yellow or green cover. Long range, gren42s are brutal. Again, you're not at any disadvantage. You're using a unit wrong if you think that any unit in this game has an inherent disadvantage.
There is not a single useless unit on either side. The only thing people seem to forget or just do not care and scream "BALANCE PROBLEMS", is that the ally mainlines are more expensive and more versatile (weapon racks). Eg:
Rifles are the only fighting unit on USF (excluding officers since you only usually have one of them, lieutenant or captain) and Tommies on UKF. They both have weapon racks to allow you to specialize them.
On the other hand, OST has grens and pgrens. Grens are defensive and pgrens are offensive. Grens are only good long range (hence LMG and cover dependability), pgrens are sturdy vs small arms fire and great on short/medium range with the bundle nade (as you can see, it's used for dislodging cover infantry) that can be thrown quite far for the punch it packs.
One advantage USF has is that they can outfit their echelons with zooks but OST depends more on stugs, paks before the big bad panther comes out.
OKW has sturms which are great early on and fall off since they have lots of jobs to do.
Mainline they have volks which beat rifles long range and struggle against tommies on any range (before the upg). That's why with OKW you also get a great starting unit that can compliment volks in those early moments. Also you have kubel which can bleed like crazy outside of cover (and induces 0 MP bleed since you can repair it). For all intents and purposes, obers arrive as the elite infantry, which, until vet2 is good but once they reach vet2 they become killing machines.
See, that's what it's all about. At least in my book. Different units fitting different faction flavors needing different utilization