Might want to put a TEC on the server CPU!
Better to get a non-He cryocooler to make your own liquid Nitrogen drip feed.
One shouldn't go halfway if you want to overclock something. =)
The thing that stops their widespread use is their very low efficiency. You need big noisy fans to get rid of all the waste heat from the hot side, and that drives up weight, price, size, etc. In nearly every application, gas based refrigeration systems win out overall.
Many consider them a niche part with narrow applications. =)
They're not so much useful for cooling as they are for achieving sub-ambient temperatures where power use isn't a problem. Extremely light and compact fridges/freezers. Final stages of quantum computers to really get down to that zero kelvin.