[Dylan16807]

Waste of what resources?

If anything I'd expect the sidewalk to be cheaper.

[godelski]

There's a difference between starting from scratch and modifying existing infrastructure

[Dylan16807]

There is.

But the post saying it's a better method isn't suggesting extra labor to do modifications. That's useful just as pure knowledge, and also it can be applied into future designs or when parts of the road wear out.

[RyanOD]

In Seattle, I've mostly seen approaches such as this as a modification. Though I see your point in a new construction situation.