The simple answer is that they work wonderfully well. I have run Campagnolo on my CX bikes for years.
The only PITA is that they don’t run Ultra Torque. This does mean extra hassle for servicing.
But I do have a set of Fulcrum RS cranks (Ultra Torque) fitted with genuine Campagnolo 11 speed 46/36 chainrings (will also work happily with 10 speed). Same as Record level.
Lovely cranks.
And up for sale! Barely used (literally 40 miles) since I went for the new 4 arm chainset instead. Ultra Torque is definitely superior to Campagnolo’s other standards. Easier to work with but more expensive to produce, hence restricted to their higher end stuff.
£120 posted if you are interested.