I've heard that the X9 is barely more efficient than average off the shelf CPUs,

and LESS efficient than top of the line CPUs

we're still fighting ASICS unless there's been some changes I don't know about 😂

The general idea is to keep hash power as decentralized as possible. to do that you need anybody and everybody mining, so using off the shelf hardware is the natural approach.

homeboy is right that large data centers with lots of compute make this less secure.

but that compute is already being used for economic purposes, I don't think anybody actually knows what the friction would be in getting lots of it on the Monero network for an attack.