As I said, their burst damage in HE is probably the only thing they have going for them. In the end I still prefer some squads of Chasseur/Dutch shock infantry/Danish shock infantry (depending on the coalition) plus Keiler. While the infantry might die, the Keilers have the distinct advantage of survivability and with AP scaling and autoloader can inflict some major damage even to higher end tanks.
Yes, that burst damage IS the only thing they got going got them. you panic them and they are useless, also they are helpless against even cheap helo transports fyi. which is the reason it's an underdog unit and I never see anyone use it. maybe that's also the reason why it works for me, people lack the experience with it, so they underestimate it.
But 2 keilers cost 120? (I forget if it's 60 or 65), but if you send just 1 and it meets any 90' pact inf, high end rpg's rape it due to low armor, so you obviously can't send it alone (the reason I don't use tanks with less than 19 armor in forests)
you know how much enemy infantry and tanks you can destroy with 120 points worth of deckungsgruppe?
the good part is, you'd also mostly only send them in groups of 2-3. there's no point sending a quad stack or multiple stacks on the same place, so they are spread out by default and do not get erased by one bomber or arty salvo.
of course one always uses combined arms, so those 2 keilers won't be alone in the forest, but neither will the deckungsgruppe.
So ultimately my point is merely that whatever mainstream infantry you'd send into forests, you'd be better off with those deckungsgruppe, the rest of your force composition (aa, tanks, fsv) remains the same.
At least I know I would because that's my experience which is consistent over hundreds of games, at times even beating several players worth of forces on my own. (razzman calls this anectdotal evidence, but not like I give a shit, everyone should use what they have the most success with, more importantly people shouldn't be afraid of trying out other people's strategies as well)