Another "don't bother to change" from me. As long as you've got decently stiff SPD shoes, they're fine for as far as you are ever likely to ride. The cleats and pedals last for nearly ever, and are as cheap as chips. And yes, you can walk normally in them. Ignore the marketing... because that's all it is.
I reckon Shimano realised they'd screwed up by designing something that was both good and hardly ever wears out, so they designed something that wore out ten times more quickly, and then had to come up with a gimmick for making out that they would be better for road riding...