Not a stupid question at all! IMO it depends on what type of edible you want to make. Oil is great for recipes that do not contain much butter, such as candies or chocolates. However making oil costs more than making butter. Also IMO the high is different when you eat oil vs butter.
Since you have 5 lbs of shake, why not experiment a bit? Make some into oil, some into kief, and some into butter and see what your personal preference is. I use all of the above methods for my edibles, depending on what the recipe is. For example I use oil for hard candies, butter for when I make caramels, and kief for pizza dough.