I used them in the army for a while and was looking forward to these coming back, they were great in BF4. the smoke rounds look like someone just used a vape and cant even hide a chipmunk, they need to be either the same as smoke grenades or produce a smoke shield (with slow reload) that can cover infantry movement. It took me awhile to figure out how to use it effectively in BF6 but only found it useful on mirak valley, firestorm and the peaks map (breakthrough defense).
The rate of fire is fine, I managed to get 20 to 25 kills per game with it, on the receiving end of it the explosions do make the round seem more chaotic but the rounds dont do damage to buildings or anything, like you stated they dont do much to vehicles (even open top jeeps). BF4 it took 4 or 5 to take out a tank.
Biggest issue is the **bleep** red icon the enemy can see from ANYWHERE on the map, pretty much telling them where to go, I also hate how easily the Mav can destroy it considering this mortar isnt an electronic like BF4 was, would make sense of the Mav had c4 on it or actually shot something but it doesnt, just point click boom.
It's crazy that they made it the 2nd to last unlock and yet its virtually useless. The screen should say "congratulations on lvl 49, and f*** you here's a mortar"