I know doing long long marathons can hurt the toenails, but do a lot of people really think of having them permanently removed? Ow ow ow ow ow! Acid poured on the nail beds? Ow oo ee eeee!
I think the grossest picture is that of people who only have the mangled ones removed, so they end up with some nailless toes and some with nails. That would look ug.
I can’t imagine running so much that the nails bleed, get mangled, and fall off.