I love mine. They are an extravagance.
Lower rotational weight and aero advantages don't count for much on gravel, but I do us mine at the velodrome (<40mph).
Boas are very very nice. I have the fangs in it so its great climbing hills when doing a CX race - although now I throw my bike over my shoulder and hike up stuff when gravel riding (i.e. this morning) to open up routes I could never do if staying seated.
(I got the $400 version half off)