Some did, back in the 1960s and early 70s at least. And my own first (DIY) amp used DIN for that reason.
However, in my own experience of both DIN and XLR connectors, I have been impressed by XLR, but not DIN (though I don’t have experience of NAIM’s particular choice of DIN). XLR is just about universal in studio, broadcast and other pro audio applications, with both low level signals (e.g.microphones) and line-level as in interconnects.