Homebrew kits are most convenient for recent converts. It already includes the most basic of materials needed in brewing your beer. You'd already have the hops and grains formulated, the yeast ready to begin colonizing your water to give you the first taste of a homebrewed beer.
Craft beer is made by a small, independent and traditional brewery and not from a mega-company. A brewery is regarded as small if it produces less than 2 million barrels of beer a year. The focus of craft beer is on quality instead of quantity.