That is what I'd like Ellie to do but she thinks the floor is just fine.
She goes outside sometimes but when I am gone she goes on the floor or occasionally a pee pad. I think letting them do both is too confusing unless they use the pee pads the majority of the time but know it is okay to go on the grass... I think I would do one or the other. I also wouldn't expect a Yorkie to hold it for more than 2-4 hours.