What is WAN used for?

Can you tell me, in simple terms, what is the primary purpose of WAN technology? Is it solely for connecting computers within a local network, or does it have a broader scope, enabling the interconnection of diverse networks across large distances? Is WAN essential for facilitating global business operations and enhancing communication capabilities, or are there alternative technologies that can achieve similar objectives? Additionally, could you elaborate on some specific industries or sectors that heavily rely on WAN technology to function efficiently?