Wow! That's a $300 full-face helmet. I've cycled for years with $80 Giro helmets. Often I can (could) average 20+ mph with downhills over 40mph+. Wearing kit attire. My helmet did save me when hit by a car as it hit the curb - and HARD. My first thought was "I'd be dead without this thing" and still probably was concussed. I never ride without it. I can see falling into a false sense of security riding along at 25mph on the road. To hit that speed on my road bike I would need a slight downhill, tailwind and be spinning my legs off in top gear and I would be well aware that I was really moving.
Road bike helmets can be dangerous. The multiplicity of vents tends to concentrate point loads. You might have been dead without your road helmet, but you might have been less dead with a multisport helmet