Well Daz it's relatively easy, because it gives you a great choice from their catalogue of posable, rigged models that can be animated in other softwares ( like Blender).
Also there's a great catalogue of clothes, hairs, furnitures, and other assets already at your disposal without the need to model them from zero.
So all you have to do is to create the pose and the animations ( like for the sex scenes) and then renders them with more ease, instead of creating everything from scratch like Rathieu did with this game and the other one he's making.
The bigger cons with Daz is that you often see similar models ( both for women and the men), whereas with this (or other 3D softwares) you can be more creative ( but you also need to know more about 3D modelling, rigging and other skills needed to create a 3D background and models from scratch).
Many devs aren't 3D modellers, so Daz is in most case a shortcut to create a game, with less stress and more quicker thanks to his immense catalogue of pre assets, that's why many prefer to use Daz and then just creating the animation using a specific 3D softwares engine.