Who can say he/she never had a phone number written on a piece of paper without being able to find the person it's supposed to be attached to ? When I was typing a number, the addressbook was looking for this number and displaying the matching contacts. Nowadays, it seems that only WinMo is doing this. (blackberrys don't, Sony Ericsonns don't, Android don't, ...)
I was also wondering why there is a possibility to add nickname to a contact if there's no possibility to search using those nicknames.