Well, I wouldn't say the preference around the world is that clear. I can remember whole articles in the 80's and 90's dedicated to the whole argument of back versus face, and growing up on the East Coast of the US (at least in New Jersey and the places south I travelled to), it was generally accepted that you call waves by the back (or just half the face size). Also, pretty much all the surf mags supported the '1/2 the face size' of wave height (Hawaiian style is a bit different from traditional 1/2 the face reporting).
As the sport became more popular, and more people entered the water, and the majority being unschooled in etiquette, let alone anything about the ocean and waves, I might agree with you that the preference in that generation is trough to crest because they never took the time to learn or know anything different. It was one of those things we used to look for to identify a shoobie or kook.
Finally, in 2001 or 2002, the scientists got into the game and started 'officially' calling wave height from trough to crest, basically because people were getting hurt by going out in what was called 3-foot surf.
As a result, and of the long-running confusion, pretty much every surfer I know calls it by the 'six foot adult' standard of waist, chest, shoulder, etc. nowadays (even in daily surf reports. Though in many surf reports still using feet, they're still doing it Hawaiian, as you may term it)
Though one difference between Hawaiian and the classic 1/2 the face size is that Hawaiian typically starts around 1/4 of the face size and as it creeps overhead becomes more like 2/3 of face size. the former is to keep people off the beach and out of the waves for the locals and the later is for impressive story re-telling of big surf stories.
One extra note is that the wave at the peak might look bigger than it really is down the face for a number of reasons. In any of it, it's all very subjective measurement except when you have a surfer standing right there on the wave, at the bottom of the trough. But then, if he's standing in the trough and not on the face, he's probably gonna get worked.