Not only does it look cooler, it also saves at least a minute. Evac All adds a handy little button that makes every unit in the evac zone rope out at the same time. Getting all of your soldiers to the evac point and having to go through the long roping out animation with each and every one of them is tedious to the point of torture. The only thing to keep in mind when modding XCOM 2 is that certain mods only work for certain versions of the game - though the descriptions and launcher will mostly keep you right.
Showing their commitment to the community, Firaxis actually teamed up with Pavonis Interactive the creators of the original Long War mod for Enemy Unknown to make sure that the modding tools were as streamlined as they could be before releasing them into the wild. Firaxis are up on Bethesda levels of supporting the modding community these days and while they seem to have left the community to their own devices, they have made it so easy for modders to really change the whole game.
