I’ll admit it, I love Grots. While this is largely because they are perhaps the single most amusing figures in all of Warhammer 40k, the cheap, expendable little green buggers do actually have several uses.
First, did I mention that they’re cheap, and expendable? As a result, they be used as a “meat shield” to provide cover saves for more important units. They can be used as greenskin sacrifices to force the enemy to assault them first, leaving the foe open to a counter assault by your Boyz. I also often use a Big Mek with a Shokk Attack Gun in a unit of Gretchin—they take the casualties from incoming fire, and if the SAG goes Boom you haven’t lost much in the way of a unit.
They’re also troops, and hence scoring units—and thus can be terribly useful for either securing your objectives or threatening your opponent’s. Remember the cheap and expendable part? For between 40 and 67 points you can get 10-19 Grots. In a recent Apocalypse game we played, a single unit of 10 Grots proved essential in holding one objective, freeing up the Boyz to go after the further and more dangerous ones.
With a WS and S of 2, don’t expect them to kill anything in an assault. In small units they can also be quite fragile (something which, admittedly, can be a liability in an annihilation game). Their shooting can occasionally do some damage, however, especially if there are a lot of them: with BS 3 they hit 50% more often than to Boyz, assuming that a S3 Grot blasta does any real damage to the target.
Combat isn’t the point, however. Grots are on the battlefield to shape the battlespace by seizing, holding, and providing cover. Oh, and they’re cheap and expendable too!