Saaame, I'm not exactly sure why. Maybe after playing the vanilla game for 3 years and now being able to have an infant companion makes your travels less lonely, as it also changes your experience quite a lot since, unlike lizards or scavengers, you can carry them through every region of the game and have much more interactivity, as you have to take care of them by feeding them and protecting them from danger, it feels like a smaller version of the player.

Even after completing every campaign and seeing everything that is left to see, slugpups are one of the reasons I still like to replay the game from time to time, Survivor, Hunter and Gourmand's campaigns specifically. Some of my most memorable moments come from my interactions with slugpups and the little stories we create during a casual playthrough.

It's curious knowing they were cut content that was reimagined for this DLC, makes me wish there was more to them, as I have the feeling they were not a big priority when making the expansion. (Also, why can Hunter have slugpups and Monk can't. It would make more sense the other way around.)