The same selling points of convenience and simplicity and sleight of hand that the Kampfe Brothers, King Gillette, Colonel Schick and others used to make straight razors disappear 100 years ago.I think the main selling point with the general public is convince and simplicity.
Quite the slight of hand making DE razors disappear from the shelves of the retail stores everywhere.
The main selling point those companies marketing departments all used was that their safety razor was faster, safer and easier to use than the straight razor, and better than the competitions product. Absolutely nothing has changed in the last 120 years.