Counterpoint. I have played without alignment for years. Many modern games are built without it. Alignment is a guide to help play your character. There are other approaches. Check out Forged in the Dark, which has alignment only as an arcing assumption, but which guides play by rewarding class-appropriate behavior.

Alignment is not necessary. If you find it a helpful tool, then use it. Make sure the group is on the same page about whether to use alignment and if so how.