"Light" in American beer parlance means it's lower in calories and alcohol content. They came about initially because there were a lot of reactions to changing diets for Americans. Lots of stuff happened at once, like a very powerful dairy lobby, increase in high fructose corn syrup, big pushes to gain weight basically. A lot of Americans actually took notice and started developing modern diet culture, and part of that was cutting out beer. Companies responded by offering beers lower in calories. They stuck around because they're less bitter.

Yea there's a regular budweiser comes in a red can. Bud light is so much more popular most people refer to the twp as bud and bud heavy. Light beer has slightly lower alcohol percentage and slightly less calories because the goal of them is that you can drink 20 of them at a barbecue even if you don't like beer.

It’s watered Down beer