>>/11788/
Ugh, the best way to see it would be through like gameplay but basically the construction ones which you want asap are the ones that get the stuff from your inventory and place it automatically instead of you having to be in range and place it manually. You might say: well ain't that fucking useless I can just walk there? Well you can also copy things, so basically you've got like this complicated part of the production that takes a lot of time to set up by hand but if you just copied it (stacked it) to one side it would just work and make more of the thing you want, well the robutts will just do that for you and like 5x quicker than you ever could even if you're the greatest factorio player that ever lived.
Basically instead of being a kind of a chore manual labor to set up things they make it an "thing appears in the place you want it to appear" kind of business instead.