The reasons to donate have already been explained many times both on Planet Debian and elsewhere; a few weeks ago I wrote a post (in Italian) on the Ninux community blog to spread the word about it.
So, why I haven't donated earlier?
Trying to donate via PayPal from Italy (and, it seems, from Europe in general) requires a PayPal account, which I don't have and don't want to have, so I contacted them to ask for bank transfer instructions. The first instructions I received were too complex for my online-only bank account, so I asked my bank for help, there was an exchange of emails, further simpler instructions from their bank, a small donation to test everything and time passed.
Finally, the good news: it is possible to donate to Conservancy from Italy (and probably from elsewhere in EU) using a SEPA transfer with minimal commissions and usually available from the home banking websites, so that it doesn't require significantly more effort than using paypal. You can contact Conservancy via e-mail to get the relevant payment data.
(Conservancy has an account in EUR which is then used to pay for expenses in EUR, so no currency conversion commission are involved.)