It sure costs less, but the pit gets countered by double indirect fire and the game is also over if you lose all of a simcity. At least as okw you can get a command panther if you pick that commander (which I usually do for flares if I'm using double isg). Medhq and flakhq are also part of teching, so you would have to include platoon cp and bofors sidetech. Still, emplacements are lulzy and awful, but I guess they're cheaper as you say..
Well, it is not really hard to destroy the Flak HQ, while it takes a large effort to just destroy one Bofors. And if you lose your Bofors, it is not a big deal (if you don't lose it outright ofc), but if the Flak HQ is down, you can basically surrender or have to rely on the single Command Panther call-in. THat's why you have to place the Flak HQ so extremely defensively, because it is pretty fragile.
Now, if you have double OKW in team games and they both go LeIG spam, then you get into problems, because 120mms get countered as well as At guns attacking the Flak HQ. But I guess if you have 2 Brits going mortar pit, it can also be cancerous.
However, since the Cromwell/Comet have been nerfed, the cheese has become less for Brits, one thing that could use some attention are the racist trenches though, which allow to cap a point in extreme safety and if destroyed you won't lose the squad, which means no real risk.