No difference whatsoever. No barrier at all also makes no difference. Building either is a costly and useless thing to do ;-)) only difference is that a Wall is5 to 50 times more expensive (guess who is going to have to pay?).
Such 'promises' are purely a way of appeasing the voters.
Here's the deal ------ we can build the "wall" just like Teddy Roosevelt built the Panama Canal -------- we are still charging a fee to get through the canal. Why not charge a 'fee' to get into the USA? That ought to slow 'em down, and the USA makes enough to pay for the wall.