Shells traverse slow, and as some people point out, the Ostwind shells should work like 5 inch guns on CVs and CAs, but a lot weaker.
IMO, Ostwinds are mostly for threatening enemy vulchers not to come close to the base, so it can buy time for friendlies to get up and fight. M16s are much more effective, but the enemy knows they are much weaker in armor than Ostwinds, so there's always some nutcase who will choose to suicide himself with the M16 MGMC. Everybody knows Ostwinds are tougher to knock out, and a 1 ping can kill you. This makes even the dodos think twice, thus, buying some time for a frdly to get up.