I think any benefit from them depends on what kind of riding you do. £800 carbon deep aero wheels are probably a good idea for racing/TT'ing, but for ordinary weekend rides I'd be tempted to go for something handbuilt (record/dura ace to open pros would be classic) and spend the rest on nice road shoes and rapha (if you're so inclined).
I think any benefit from them depends on what kind of riding you do. £800 carbon deep aero wheels are probably a good idea for racing/TT'ing, but for ordinary weekend rides I'd be tempted to go for something handbuilt (record/dura ace to open pros would be classic) and spend the rest on nice road shoes and rapha (if you're so inclined).