[ghaff]

Many times they're actually "temporary visitor" visas or something like that. Which, as you say, typically prohibits working for a local company, otherwise use local resources, etc. But I've attended business events all over the world. With just a few exceptions, e.g. China, there's never been any question of getting some special visa--which usually requires letters of introduction and so forth--to do whatever combination of business and pleasure I'm there for.

That said, I'll note that e.g. Indonesia 30 day visa-on-arrival seems to theoretically be only for non-business purposes but when I've gone there's never been any question of using anything else.