in most situation: yes! because they even make dmg when bounce...hit mostly everytime (homing) and even hit often the rear-armor from tanks....very great this thing
As I said, if you want axis to use zooks/piats/ptrs instead of shreks (and maybe give those shreks to the allied factions), every single allied player will take you up on that offer. Shreks themselves are the single best handheld at weapon in the game by a significant margin (no, -18% accuracy at max range does not make up for +50% damage and +50% penetration). Sure, allies have more efficient handheld at carriers (usf/ukf res can both get 5 man squads and they are cheaper to reinforce), but that's the only thing keeping shreks in check. I won't say that double shrek fusis are necessarily op, but there is definitely some potential for op-ness there.
For another fun fact, if you want to kill a sherman at max range, you need 8 zook penetrations. You only penetrate 70% of the time, so you probably want around 12 zook hits. You hit about 78% of the time, so that's about 15 zook shots.
Now, look at how many shreks you need. Shreks deal more damage, so you only 6 shrek penetrations. Even better, every hit penetrates, so you only need 6 shrek hits. At max range, you have about 64% accuracy, so you need around 10 shrek shots. So essentially, if you are fighting a sherman, 2 shreks are worth 3 zooks, even after you take their worse accuracy into account.