Inferior to what?
So you want to know now then?
The first lesson...
There are a series of test carried out across the world to prove that helmets can pass a certain impact and this gives an estimation as to how well a helmet performs.
The Snell B95 is recognised as the toughest and that there are many helmets out there being worn that cannot reach this standard
The classic case is the UK / European EN1078 that is so watered down as to be virtually useless.
In fact if you wish to race or take part in a Triathlon in the US than EN1078 endorsed helmets are considered inadequate and banned!
Snell B95 requires more rigorous testing and a helmet that has not passed Snell B95 cannot make an evidenced claim to be as efficient as a helmet that does and when it comes to protection, the proven capability to prevent injury is inferior.