It's the height differential people are talking about. I believe standard oly shoes are usually a ~one inch heel, but they're also elevated a quarter inch in front, such that the differential is .75". The Rip shoes are like .75/.25, so only a half inch differential.
Honestly, standard oly shoes are absolutely fine, no need to go the .5" differential route. The only place it gets slightly disadvantageous is with deadlifts - with a good sized heel, deadlifts are a little harder (the bar is moving a greater distance due to your own elevation). I prefer not to deadlift in oly shoes anyways, though, so you can always just take them off. Deadlift slippers, for example, can be ordered online and are dirt cheap.