I'm looking for evidence that it's "overrated". "Overrated" here means they're valued as a tool to improve cardiovascular health, when they don't provide that benefit.

I've never actually seen a standing desk advertised, or even recommended, as a tool for improving cardiovascular health. So I don't see how they can be "rated" as such.

I use a standing desk sometimes because it breaks up the monotony of sitting, and because sometimes I want to stretch my legs. It does well in that regard, and that's what I see them being advertised for.