There are downsides to larger signatures even if part of them is
out of view due to the scrolling box. They require additional
server and/or database space for saving, more widgets equal more
work for the server whenever they load, and lastly - since sigs
can't be turned off as far as I'm aware - it causes users to
download more data (mostly from the widgets or other images) each
time they open a thread or something with signatures in it. Which
is not very fun if someone has a slow connection or limited data
volume (like on a smartphone). All for content that they can't even
see without scrolling and that is not essential to the site itself,
so to speak. No support.