That helmet would be good for light riding where someone wants additional peace of mind (whether this is valid is not known) but that thing is not good for DH.
I have seen the chin plate of Giro Mad Max II's ripped off in highspeed crashes, I have seen a TLD D2 hith a huge dent and hole in the chin plate. Hell I never saw the crash, but saw a guy with broken jaw (really disgusting, blood gushing out of mouth bottom fron teeth on two totall different levels) and this guy uses a Giro Mad MAx II.
No helmet can offer total protection, but some offer better protection, there can be problems with the neck in accidents when the helmet doesn't fit properly or if it has a longer back part which goes down the neck.