Those little bullet icons are on the bottom left are the stock of available bombs.
After they suicide the first ship right off the bat, they go into a bomb-dropping spree, and there must be some point advantage to using the bombs or chaining bomb attacks together, so the purposeful suicides give them the extra bomb stock to utilize for that purpose. (I'm guessing)
After each death you get an extra row of bombs again, so I think the suicides give them twice the bombs to use or something... Just a guess though, as I had the same thoughts when I first watched the Insansity dvd as well.
Just a side note, That big "hookshot / bazooka" power move which anchors to the top of the screen is pretty cool though. I haven't played the game yet though unfortunately.