kv8 in some situations is one of the few soviet units that can force a mass retreat.
these are the german units that have the same effect:
mg42
scout car
flame ht
p4
ostwind
why would you actually retreat conscripts from a scout car? guards/at nades/30mun mines, conscripts shooting from cover. If the enemy makes multiple scout cars his fuel is so screwed your first tanks will rape his whole army
if you dont have your own t34s/su85s/zis by the time a p4 or ostwind comes out, you've probably been driven off the map since the start
mg42 and flamer halftrack (squishy, shorter ranged, and with weaker dps than a kv8, I should note)
DO force the soviet player to react.
Snipers, fast t70s (but also t70s in general), kv8s, su85s, and so on force the german player to react specifically to those units.
The difference is a mg42 and flamer halftrack can be killed easily by tier1 units (molotovs, flanking, at nades, mines) while su85s and kv8s, even well micro'd snipers, are not so easy.
When MG42s and support teams rightfully get nerfed for flanking damage and probably suppression, what else will soviet players be really able to cry OP on then?
I'm not exactly original stating that the soviet army has space dominating synergy with multiple builds, like su85s + guards + snipers + scripts for screening that the german's cant match. A pro soviet player will use the discrepancy in building cover and t1 harassment to contain the ostheer on their high value resources defensively (or cut them off completely), which means itll be game over when the soviet player techs faster.