Hah! Knew what it was going to be about just from the thumbnail. I’ve been telling people (mostly my immediate family...over and over and over again) about fake DOWNLOAD buttons and other “UI hacking” for years!
Well, you don't strictly HAVE to, as to a degree, water with a temperature gradient will move itself. Yes, the heat transfer interface between the stock air cooler fins and the water medium isn't the best (and frankly there's still probably air bubbles fouling up the works between several of the fins), but the main issue is it adds an extra step between the CPU and heat removal, which is that many more components to risk malfuction - and any malfuction at any point will lead to complete failure with damage very quickly. If his DIY acrylic tank springs a leak, his motherboard's toast. If he mounts it in a case, it's going to turn the center of gravity 90 degrees, and change the stresses on the glue holding it together, which could lead to leaks, or put additional flexing stress on the motherboard where the cooler is mounted, or separates the interface plate from the CPU just barely enough to impede heat transfer.
The pump might go out, but at least that would be a slow failure, and isn't any more of a risk than a conventional water cooling solution (which I already think is more trouble than it is worth in 99% of builds)... And like he says, he's going to face heat saturation at some point when his ice melts, if he doesn't switch to some kind of cooling radiator - which begs the question, will it continue to cool well if the water is NOT near 0 degrees C?