Interesting discussion - a few points. Fans for WC are likely to be running slow (this is after all the point) so the discussion on whether WC draws more power based on fans alone is, frankly, odd. Over and above air you have a pump - that's it. Personally I'd say this isn't worth discussing - it's negligible.
Heat however is not - WC does absolute wonders for this and for GPUs full blocks drop heat massively vs air across the whole board (VRMS are super toasty) and yes this will make a difference to the clocks you can hit (consistently even in hot weather) and the longevity of components. You can move heat away from things far faster (and in my build to an external rad which means i'm not dumping hear into the case at all) which also stops surrounding components for getting hot too.
Noise was the real reason I started on the moist path - well over 10 years ago - and my current rig was built and 'run in' on air. It's a lot nosier. A lot. I admire the progress that air cooling has made but it's intolerable for me.
Would I recommend it? No, not generally. If you enjoy a challenge and like building stuff (I do) then it can be rewarding but there's a lot to learn and a fair bit that can go wrong until you do. The reward is a cool quiet system but it costs time and money to do it right. WC components do last a long time but they cost a fair bit nonetheless.
That said why justify doing something you love, especially on a forum filled with idiots spending vast amounts of cash on overspecced PC equipment

?