The fluid would probably be fine for applications that call for low grade heat, like radiant infloor heating. You would need a conventional radiator after the flooring as well though, essentially specced to remove the full heat load.

The biggest problem with these kind of dual use circuits is that you often need a relatively robust system of bypasses and controls to give you flexibility to control your secondary user of the heat and also deal with its often intermittent nature, unless your system is so small that you can always just run it full out.
I looked at doing a dual radiator setup before I settled on just using a bunch of closed loop coolers for my gear. It would have consisted of radiators mounted in the cold air return vent of my furnace (with a variable bypass valve), with the radiator output running outside to another radiator to cool the water down to ambient before reentering the loop. You could obviously continue to harvest heat from the water before you sent it outside if you wanted to; I already have a drain water heat recovery system but that would be an obvious addition.
In the end it would have been a lot more efficient use of the heat plus it would give lower temperatures to all the mining gear, but without years of expected use it just didn't make sense to devote the time and cost to it. Simpler to just have some units outside and bring more inside as it gets colder.