I’ve built with them. No issues. They came stock on my mountain bike too.
The Kinlin rims I bought from bike hub store were offset and not advertised that way. Seems possible that a lot more out there are doing it, just not talking about it.
Seems that a lot of wider 30+mm mountain bike rims are offset until you get into the fat range.
I’ve never seen a road rim offset. I’ve heard of their existence.