Giving credit to the family (Yes, I've seen the show) - OHS seats are currently available and do meet the same safety standards as 5 pt harness seats. Even our much favored "cheap seat" - the Cosco Scenera comes in a OHS version (which I'm thankful is $10 - $15 more than the 5 pt. Scenera at Wally World).
Yes, a seat with a 5 pt. harness is preferred, but OHS are useful in some situations.
Some people see them as easier to use (the straps don't twist, only one buckle to buckle) - since the "Best" seat is the one that fits the car, the child, and WILL BE USED CORRECTLY EVERY TIME.
Also, for someone with fine motor difficulties or who lacks/limited use one hand, an OHS might be preferable. Personally, I've found them to be more difficult, but I've never tried to buckle a child into a 5 pt. harness using only one hand.