Commercial Techs - Do you ever use "add-a-wire" kits instead of running C-wire?

[bhensey]

I've seen lots of new residential thermostats use hacks to work without C-wire, but not many in commercial spaces. Does anyone use "add-a-wire" kits instead of running new wires when upgrading thermostats? They seem much easier and cheaper to add, but I'm wondering whether there's any downsides that I'm not aware of — do they come off as hacky or unreliable to customers?

[bhensey]

Thinking specifically of the "Venstar add-a-wire kit", but there's a few different brands