A temperature display itself probably wouldn't be of much use because the CPU will reach an operating temperature and modulate the frequencies/boost to avoid exceeding it. One user could be enjoying full performance at that temperature, while another user is running at 1/10th the speed.
The OS does see the perpetually fluctuating frequency state of the processor, though, and can monitor it over time in a correlation with the temperature and display a simple aggregate performance metric, flagging as a system alert when performance falls below a set threshold. I've had relatives whose system saw a dramatic, very noticeable usability improvement after a couple of quick bursts of compressed air.
In-laws were going to throw away their computer, random freezes in the summer. Needed a thorough clean, "good as new".
PC World/Microsoft lost a sale though.