Generally no - the chin bar mechanism is a weak point. However, premium modular helmets like Shoei Neotec II and Schuberth C5 approach full-face protection levels. Look for DOT and ECE certification.
Convenience is the main reason - easy to put on glasses, drink water, or talk to people without removing the helmet. Touring riders love them for fuel stops and navigation.
Yes, typically 2-4 dB louder due to the chin bar seal and additional joints. Wind noise enters through the mechanism. Some premium modulars like Schuberth are engineered to minimize this.
