I have a smallpox immunization scar on my upper arm. It's about the size of a quarter and not very ugly. It is trivial compared to the disfigurement that typically came with contracting actual smallpox.

Also, being dead is terrible for your skin, so.

And anyway, if everyone has the scar we've all got the same tiny deduction in 'attractiveness,' so it cancels out I guess.

Yeah, but the scar is fairly small and can be in a place that isn't showing. That would be the least of my concerns ...

Anecdata, but my smallpox vaccine scar is a small, ~1cm spot.

The risk of "inadvertent autoinoculation" was my bigger concern - if you touch the site before it's fully healed, you can spread the vaccina virus to other parts of your own body. In rare cases it's been known to cause blindness. Fortunately a Tegaderm dressing kept it contained to my shoulder, but damn did it itch like crazy for those few weeks.