I worked with a company that did a proof of concept for these "oil bath systems" It was just like in the photo, a rack on its' back immersed in a tank of oil.
From a cooling standpoint, it was great, from a parts replacement, it's a disaster waiting to happen. It's not how hard it is to replace the part. We installed a small crane above the rack to make it easier to lift the server up out of the bath, so we could lay it down and replace mem/cards/SSD etc. A 1RU server can weigh anywhere between 30-40lbs, and a 2RU server can weigh almost 70lbs.
We had to surround the bath will a perforated rubber mat, as oil+typical datacenter floor is a huge slip hazard.
You've also got to install pumps and a heat-exchanger. Reminds me of the old water cooled mainframes. Just with way more plumbing.