This is how I interpret alignment: it's part of the D&D and it is a quick indication of how to role play something.

Background, alignment, bond, flaw and traits are just prompts to help you role play a new character or remind you how your roleplayed that character 10 sessions ago.

Alignment also helps provide suggestions on how the gods would view an individual.

Also alignment also indicates which inner plane that your soul goes to when you die. Ya know in case a character dies and they want to do a rescue mission for your soul.

And if a player says "my character Lawful Good," but they seem confused on well everything! just talk to them. "Hey Jim, when you play, we're just seeing a lot of, well Jim but like a confused version of yourself. Since I read your 8 paragraph backstory that involves the murder of your wife and children, murdering your father and escaping a cult of Lolth, may I suggest a few tips on how to roleplay that? "