It's a waste of money because there are lots of reliable 30mm depth aluminum clinchers that come in at similar weights and won't fail/delaminate when over heated going down a hill. And, they cost 1/3rd the price. Carbon is cool and sexy but for this application there is little if any benefit for the substantial extra cost.
At least at 50mm, you can say you are getting a very marginal aero benefit if you are willing to accept the trade-offs of carbon clinchers.
Carbon clinchers IMO are a fundamentally flawed product. You do something as basic as braking while going down a steep hill and you can easily exceed the temperature of the resin and ruin a wheel that costs $700-$1200. Do the pros ride clinchers? No.
Watch this guys videos:https://www.youtube.com/watch?v=ET1jRVynOBA
The November Cycles blog has loads of good information. Here is why they stopped selling carbon rims:http://www.novemberbicycles.com/blog/20 ... arbon.html
To sum it up:
"aluminum clincher rims are simply the better choice for nearly every application (if you’re going for the TT worlds, carbon’s a good choice)."
Sorry, but I think you generalyse a little too much. Roval CLX32 clinchers are 1290gr with a better aero than their previous clx 40. If you can build a bullet proof alu wheel of that dept and <1300 gr, >25mm wide, that is stiff enough for 90% of us here, you've found the golden grail!! Do not forget, the light weight of the Rovals is thanks to the rims, not thanks to ridiculous light hubs like Extralite ones. As a result, they 'should' feel lighter on the road than if they had done it the other way around. You can build alu wheels with Ryde Pulse Comp rims and extralite hubs, total weight : 1280 - 1300 but aero will be poor, hub reliability is
and at that weight, you have to lace them with 20 and 24 spokes. Maybe not enough if the rim itself is not overly stiff.
OK, Rovals sells for a very steep price tag, but not more than other high end wheels like Zipp, Enve etc. Your point is valid if those Rovals were near 1400gr, like Steath Wheels or FFWD 30mm's, but the Rovals are in an other cathegory weight and width wise. Everyons has his opinion of course, and I respect that, but you have to take all the facts into account...