There's got to be some reason, but I suspect it isn't as big of a reason as they might suggest. All I can say is that with easy-to-access fittings you're more likely to get them greased properly than those that are harder to access. I know that I have one that it's questionable whether I am in fact getting enough grease in to: have to lift the loader and then, because I'm outside (currently no garage or barn to work under) I find myself staring into a very bright background of clouds or sun, which leaves me feeling like I'm "shooting in the dark!"
Yes on the tail wheel. Large gap and the grease just seems to get pressed out. Maybe set up a drop-feed to it?

I have a new tail wheel, because I busted the old one (if it'll break, I'll break it!), and this one tends to dry up more quickly than the original one and the shaft is already scored (softer metal?).