You get a pretty decent multiple of performance on power vs. intel. Probably something like 4-7x for common use cases.
Generally speaking, you buy the hardware because your workload needs the single core performance, or you're arbitraging vendor licensing costs for software.
Also, IBM's bread and butter is "peaky" financial services and gov't business, so they have business models that makes it work from a $ pov. You can buy a box with 100 cores, pay for 20, and lease 30 more for a few days to meet your peak demands for tax/christmas/billing season.
Generally speaking, you buy the hardware because your workload needs the single core performance, or you're arbitraging vendor licensing costs for software.
Also, IBM's bread and butter is "peaky" financial services and gov't business, so they have business models that makes it work from a $ pov. You can buy a box with 100 cores, pay for 20, and lease 30 more for a few days to meet your peak demands for tax/christmas/billing season.