I have those peaks on my lids - ideal for when the sun is low. Only downside is that my Bell lid, at least, then didn't have the capability to fit a visor if you wanted to use it in an open car (or kart).
I'd still contend that open-face is far more convenient in a closed cockpit and, if you're needing that small extra bit of protection, you're probably in worse trouble than you realise. I'm also not sure how I'd manage in one of those crazy series where they make you jump out and back in again
Seeing the harness buckle in a race seat (quite upright) in a full-face can be quite awkward. The cheek pieces on an open-face extend quite a way forward so offer much of the same oblique protection. As an addendum to this, a school friend crashed his moped into the back of a parked Land Rover. They reckon that having an open-faced helmet saved him from having his neck broken.