Shipping skids which are to use here are basically the heavy duty wooden boards made of hardwood and designed especially to handle a lot of weight as those of shipping containers! So in a bunch shape like in these installed pallet sofas, they may not be very easy to move in your directed direction! It may put you in great trouble if you want to shift those heavier sofas to either location of home!
This problem has also been solved here so wisely! Use of hardware casters can provide of the ease of pushing and dragging to them and rolling movement will also be awesome for a showy industrial look! Metal touch will surely give a functional and visual boost to these handmade pallet settees along with the ease of their shifting to garden, patio or home front porch! Do add the wheels if you have built a little bit heavier design of whole pallet settee!