izigame.me

The Little Ones DLC adds kids into the game. They can do stuff if you teach them first like rolling up cigarettes so you can trade it for food and they are a morale boost for all of your survivors. When your survivors are depressed or worse outright broken they can become very annoying to deal with but if you got a kid and the kids happy most of the adults will be happy too. Similarly if the kid gets sick or anything everyone will be thinking bout the kid. Just like the main characters themselves the kids do share their own opinions on whatever is going on.
+They can be useful if you teach them stuff they can go and do those things when the adults are busy with something else or sick so they're resting similarly even if you don't teach them anything just keeping them happy is a morale boost for your survivors which is something you may desperately need at times. Depressed adults suck at surviving.
In all honestly there isn't really any downsides to the DLC that I can think of. I guess I could say "makes survival and essentially winning the game harder because now you have one more mouth to feed" but thats kinda the point of the game so yeah. Its just extra characters who can do stuff if you teach them and even if you don't they'll make sure people are depressed a lot less often.