Large, well-optimized services are running at high CPU utilization all the time. But there's a long, long tail of services that are running well below 100% utilization almost all or all of the time, and it's not just hobby stuff. Vulnerabilities in those services are still real and can be very important, and trading some otherwise idle CPU time for an absolute shield against memory safety issues is a good idea. Even for some services that do have high CPU utilization it may be a good trade to pay for more CPU to get that shield in this new world.