This thing is a glorified truck with a few rockets on top,to put it plainly.it is also at the same BR as its contemporary,the calliope,which is just so much more powerful.in order to justify this BR lowering,we need to look at 2 aspects of these veichles and compare them
armament-starting off,the panzerwhefer has 10 158mm rockets ready at any most,which are slightly larger than the calliopes,and only 10 reserve rockets,so you have to be percise with them to use effectively,which is hard considering the strange ballistics (and the fact you can blow yourself up with it),and a 7.92mm MG42,which may seem great,but its ROF makes it overheat way too fast,and it has a limited traverse.when we look at the calliope,it has 20 114mm rockets ready at once,which are slightly smaller than the panzerwhefer’s,but double that of the panzerwhefer,and has 2 more “reloads” of rockets with 40 reserve avalible instead of 20,a 75mm M3 cannon,which is amoung the best in anti infantry roles and decent at AT,a 7.62mm M1919 which overheats a lot slower and still kills really fast.
armour-the panzerwhefer has abysmally bad armour,8mm on all sides,the thickest armour is the damn tracks,need I say more?even BR1 AT rifles will have a field day against this truck,hell even artillery strikes kill it.the calliope on the other hand,has 50mm on the front,and 38 on the sides,woth turret armour being more than these,it dosnt have as much armour as other veichles avaliable,but it can still survive a shot and trades armour for firepower.
This going to BR3 would make the very noticable power difference between it and the calliope justifiable due to being seperate BRs,and this thing is a premium,so it wont be spammed as much as things like the P38 or P47 by far,and the axis contemporaries for rocket veichles are lacking in the capabilities allied veichles do.