What would be the ramifications of using all oil in this recipe?

I think it could work, except when you substitute oil for butter, you don't want to do a strict 1:1 ratio. Aside from the fat, butter also contains water and dairy solids. So usually they suggest you do a 3/4 to 1 replacement. Since 1/4 cup equals 4 tablespoons, you'd use 3 tablespoons of oil instead of the butter.