Strictly speaking, if Barth delays me sufficiently there will be no war in France; and if there is, I'm going to get the toys anyway. What I won't get is a full recharge of my losses if I take more than 10% casualties. Any losses above that will reduce my replenish by proportion. (Roughly speaking for example, if I suffer 11% casualties, I'll only replenish back up to 99% strength.)
Any political points I manage to spare / gain in Poland, I can spend on France, but I'm not sure what I can spend them on. Without historical variants, there aren't many valid pre-scenario cards to buy. (The engine allows me to waste points on them anyway, but to no purpose. There are two valid choices pre-Poland which I'll explain in the AAR.) Once I'm into the operation, I can buy another infantry division every once in a while as I gang up points. Is that it? ...maybe? From a campaign perspective, the goal is to save up enough polipoints to help with the end-game invasion of Britain -- which we aren't planning to do.
Unlike more PanzerGeneral-ish games, I can't spend points during a mission to replenish troops, much less upgrade kit; I don't think I can upgrade kit (much less buy extra units) between scenarios later.
I mean, sure, I'll buy a few more infantry divisions as I get them, but I'm wondering if I should do that now in Poland so they can get some experience maybe -- but that only makes sense if they carry over into France. Otherwise extra divs only make sense to tip a balance in case I'm risking losing Weiss.