CPU (especially for operations like XOR for checksumming) is basically free.
'Premium storage media'. I've worked for vendors in the enterprise storage space for the past 17 years or so. Even the most expensive drives still fail in spectacular ways, from the oops (you asked to write to block 64 but it actually wrote to block 2048, but only 1/billion operations, and that's silent corruption) to the catastrophic (flying height issues, bearing issues, oil issues).
SSDs, while much better, also have software (firmware) bugs and also media issues. Trusting the media is a bad idea.