[antisol]

Indeed, it's a terrible reason.

Why should you have control over what indentation width I choose to use?

There are a bunch of reasons why I might want a narrower or wider tab width. Most obviously, screen real estate - I might be coding on a tiny device.

When you do indentation and alignment properly (tab for indentation, space for alignment, as others have said), it's formatted the way the writer wants, while also respecting the reader's preference for tab width.

Spaces for indentation is incorrect, pure and simple. And the war is not "won".