I appreciate its performance (versus the less powerful chips I have tried) and it should age rather well as software becomes more demanding. For me it's a rather silly debate... the custom loop costs far more than the CPU and it's completely unnecessary... and in this case its "horsepower" is sure to be used over course of its life (it's been in three builds to date)... one with a 1080 Ti.
I wanted a hardline loop (my first) and why bother if it's hidden within a case per se. I have also built Thermaltake's P1 and P3 open air cases and enjoyed the challenge of making them "presentable" It's too easy hiding a PC in a box. :)
In this case I appreciate the "view" and don't mind my work being on display.
Cable management is a bear. Originally I was going to use custom cables since they are so exposed. However I tried "hiding" the fan cables with tubing and afterwards thought it matched the build to a large degree so why not try the rest... less than $10 of tubing that can be instantly removed. Doubt it would work with any other build however so far I like the look as it plays to the theme.
It is rather polarizing. I didn't like it when it first came out. That is until I wanted to feature a custom loop.
As posted above I had the same build with and without a 1080 Ti and didn't notice any difference in my experience. As for my "tasks" I simply find the PC snappier compared to lessor processors.
I'm on a 43" IPS panel at 4k 60Hz. I do notice Ubuntu's video driver outperforms Windows although I don't find myself waiting on either. Bottom line I used a 1080 Ti for six months and sold it at the crest and it hasn't been missed.
Now much like the custom loop I could add one down the road for the heck of it. I debated adding one however with no performance increase (based on my usage) and new cards around the corner I passed. Based on my usage the fans never spin even on the low end cards (such as a 1050 Ti) I saw even less need to water cool it.
A custom loop is totally for fun. As stated above I had a Corsair H75 in a previous build and it was more than capable. CPU wise I don't consider the i7-8700K to be "insanely" powerful rather a middle-of-the-roader that should have a decent life cycle.
Two builds ago I had a AORUS GeForce® GTX 1080 Ti Waterforce WB Xtreme Edition 11G with the i7-8700K and found I only stressed the CPU...
Even though the rad is only 30mm I agree cooling isn't in play. I have been over 5GHz with older firmware - via a 120mm AIO. The latest firmware doesn't handle auto overclocking as well and I haven't bothered to mess with it myself.