A native app would also allow you to access different market segments. E.g., I work with a fair amount of DOD-controlled information, and storing it in a cloud is not an option. I'd be all over an app like this that allowed us to use local storage.
Having used Visio and Diagrams.net, Visio really is the least productive one. Constantly fighting with the unpleasantness of applying little tweaks made it my 3rd choice. 1) Diagrams.net 2) PlantUML 3) Visio
I work as an architect for a consulting and off-shoring megacorp. I mainly work for European clients in the oil and gas sector, but recently have worked in finance too. I find Visio (or any visual diagram tool) useful for hacking together a diagram collaboratively.
I also have a side business (me and a co-founder), and I'm planning on making the plunge and going full-time on it in the next few months - there too I've used Visio, because it's what I'm used to, and I get a license with our Microsoft Action Pack subscription. Here though, I'd probably prefer to move to a declarative model, like PlantUML (I only recently found out it works with icon sets, so can do things like nice architecture diagrams too).
