Speed of light is very relevant for actual performance sensitive software, not just shitty overly chatty trash.

While in practice the latency is over an order of magnitude larger, the speed of light round trip distance between two sockets on the same motherboard is likely on the scale of 1-2 nanoseconds which is already several cycles. Once you're talking about warehouse sized datacenters the speed of light distance can get into the microseconds even in a straight line through vacuum/air.