Sometimes the extra toes grow weird and need to be removed.  Or they
get stuck on things, get evulsed and need to be removed.  Other than
that, there isn't any real concern.

-L.

Not really. Polydactyl-ism (?) won't  affect the cat's personality or
overall health at all. The biggest concern is, the extra claws usually
don't retract, so you have to be extra diligent keeping them clipped,
or they'll hang them. Also, some polys' claws grow in such a fashion
that they turn completely under and ingrow into the pad. In extreme
cases, the vet will remove the claw. Otherwise, just keeping them
clipped should do fine. But warning: You've got a cat with the closest
thing to an opposable thumb there is...a smart poly can use that
"thumb" and become a master at opening cabinet doors.

Sherry

They probably mention it because some people, like me, find those huge
mitts adorable.

I think I've also heard the old wives tale that cats with extra digits
are better mousers ... so maybe mentioning they're polydactyl will get
them adopted out more quickly.

Not that I know of.  Unless it's the sort of polydactyl whose paw pads are
in 2 main sections.  In this case, the extra claw(s) may be facing the other
part of the paw's pad & may need to be kept *very* clipped - in order to
keep the tip of that (those) claw(s) from abrading the opposing portion of
the pads.

Cathy

One of my three cats is a poly and the only thing that is different is the
extra claws to clip. She is a wonderful cat and her paws just make her more
interesting.