[hedvig23]

I would agree with the comment you're responding to, too often in tutorials or especially in off hand comments here, I find their usage to assume some common but unindicated convention or subtext and obscure the concept they're trying to convey.

[jiggawatts]

They’re the programmer equivalent of ‘x’ and ‘y’ in mathematics — which programmers don’t use as generic variables because they’re used for “math” embedded in code such as coordinates or measurements.