The only concern I would have is if there is an over voltage crowbar circuit. If there is then is no concern for the Cube on failure. I think that the power supply is a switching supply and I an not familiar with the failure modes of that kind of supply, they may fail in a manner that does not produce over voltage. Linear supplies have a failure mode of the voltage regulator transistor shorting in-to-out thus producing over voltage.

If it is running and under maximum current I see no reason to think it would fail in a room temperature environment.

Sure it is lower cost that an ATX type supply but it is much simpler with only one voltage and no cost for a plethora of cables.

There may be concerns other than those I have considered and I would be interested in hearing them.

I just ordered one so I can inspect it and in a few weeks when I get a chance I'll try it.