Good style involves choosing appropriate tools. Given a situation where no return value will be used, I tend to expect someone to pick the tool which returns no value...
But map in void context does not return a value. No function in void context returns a value - it can't, because there's nothing to put the value in. That return values of functions are context driven is a very essential thing that makes Perl what it is. It's not map that decides whether nothing, a scalar or a list will be returned - it's the context. And map doesn't behave any different than any other function.
By passing up the more appropriate (and more obvious) tool, he has obliged me to go looking for something subtle which was not there.That sounds like "for is the more obvious tool, because it's more obvious".