Xyz makes sense because that is what those axes are literally labeled, but ijk I will rail against until I die.
There's no context in those names to help you understand them, you have to look at the code surrounding it. And even the most well-intentioned, small loops with obvious context right next to it can over time grow and add additional index counters until your obvious little index counter is utterly opaque without reading a dozen extra lines to understand it.
(And i and j? Which look so similar at a glance? Never. Never!)
There's no context in those names to help you understand them, you have to look at the code surrounding it. And even the most well-intentioned, small loops with obvious context right next to it can over time grow and add additional index counters until your obvious little index counter is utterly opaque without reading a dozen extra lines to understand it.
(And i and j? Which look so similar at a glance? Never. Never!)