The first sentence is a valid reason: > Because the browser nowadays is an "operating system" that needs to be capable of handling all manner of dynamic softwa

The first sentence is a valid reason: > Because the browser nowadays is an "operating system" that needs to be capable of handling all manner of dynamic software: maps, video, image editors, games, etc. If frontends didn't use the "OS" capabilities of the browser, how would one build a multi-user real-time text editing app like Google Docs? Edit (and off topic): Writing this comment gave me flashbacks of using Mapquest online for driving directions before smartphones. You had to print the directions out and bring them to your car on a piece of paper. It worked though!