You gotta understand, what sells. The typical user only sees one thing and cares about one thing.
For cameras, it's megapixels which means little to nothing usually, obviously sensor size and lens are more important to me.
For audio it's watts, which mean nothing because there are way more variables involves than just watts, plus any gear that it's main focus is the wattage is most likely a piece of junk anyway and highly overrated power wise.. Do I have to get into Sony's lies?
For cars it's horsepower, also way more involved than just a number, ever heard the term power to weight ratio?
There is always that one key number or word that a company or should I say companies can slap on a product, and it will grab peoples attention, usually it's a big number.