Well yeah you could play without an account with a cracked launcher
At first, there was no launcher there was just the Minecraft.jar file which you could launch to start playing. That's what the parent page is doing; it's just having us download and run the game, no need for a launcher.
Yes. Downloading a game file you don't own and running it is called piracy, so beware of possible legal ramifications.
Ah cool I didn't know, I thought the download of the actual full client was gated behind a login since even third party launchers seemed to require you to log in to play, good to know!