Originally Posted by Teeps
Followed by usefulness, to TiVo.
Your argument would mean that half the information currently on the System Information screen wouldn't be useful to TiVo. The majority of the information there is for the customers benefit such as Recording Capacity/Free Space and MBT temperature. I could make a full list but that would take up a lot of time.
The enthusiasts and professional installers would find having the internal and external hard drive temps useful to troubleshoot problems (like the expander getting too hot in an enclosure), and as to cost, there isn't any because it can be put into a software update next quarterly rollout.
It's not like it would require them to completely redesign the entire core structure of how a TiVo works, it's cosmetic. The drives already support it through S.M.A.R.T.