If you're submitting an eight page conference paper you're very often hunting runts (short lines ending paragraphs) and rewording for better justification, especially on the first page and even more so in the abstract.
First-page space is at a premium because you want the reviewer to scan the introduction well, and it's great if you can fit a key figure that explains the concept on the first page.
The game's probably very different now that there's such a flood of submissions but when I was reviewing I always saw messy alignment on the first page as a sign the paper was probably rushed, and usually I could see that elsewhere in the paper too.
First-page space is at a premium because you want the reviewer to scan the introduction well, and it's great if you can fit a key figure that explains the concept on the first page.
The game's probably very different now that there's such a flood of submissions but when I was reviewing I always saw messy alignment on the first page as a sign the paper was probably rushed, and usually I could see that elsewhere in the paper too.