Yeah, unfortunately meanwell are not there yet with their drivers. Inventronics was the drivers I was thinking of from my experience here. In any case, even 1.5 amps at 350V is well and truly lethal.
My 'how to' was not intended to be a full build, else I would have explained things in a lot more detail and completed it, it was simply to show a way to recycle power sources you may already have access to on the cheap, as you note it could be a PC PSU OR in my case currently a 600w Dell server PSU.
The Xbox PSU is 150W, so it's really 12 amps and I believe also come in a 200w version. Also MOST decommissioned servers will also have at least one PSU that are at LEAST as good quality wise as the $25 driver you linked to.
The actual source of your power in this example is really an example, it just happens to be that these ones can be found at garage sales, flea markets more or less for free.
I run Osram Optotronic drivers rather than meanwell when I just want to power a single strip, I can pick them up for $15 but it's horses for courses really.
I think there maybe a bit you are missing here. For example in this configuration it is possible to run 2 strips off a single PSU, with a boost converter each or in parallel, if you wanted to run the PSU at full clip you could run 3 strips off one PSU for 27K lumens.
Also let's say you 'jerry-rig' a 600w dell server power supply, You can then just use the modules to distribute the power to the strips. If one fails, it's one strip, not all of your lights. IF you are really paranoid about a failure, then you can rig 2 PSUs to run in parallel, so long as you don't use more than half the load you have redundancy, or you could use four and and have 1200 watts or redundant quality power. Use a single driver and you are screwed if EITHER the driver OR one of the in series COB's or strips fail. It provides a flexibility/redundancy that a single driver rigged in series doesn't and it's all at a safe low voltage.
I run these boost converters potted in resin on my boat for all my cabin and deck lighting, I've the modules up so I can swap them out easily and carry 2 spares precisely because they are generic, happily in 2 years have not needed one, and most grow rooms are going to be less hostile than my boat I would think. And at 1-3 amps they are hardly working at all.
Also, the example was in no way completed, as in it was little more than a bare breadboard example and of course the parts would normally be housed and insulated in some way. This literally took me less than 15 mins. l'll do a proper full build shortly. Cheers.