The whole CC/financial score thing doesn't make much sense. We have a bunch of CC that are not used however cancelling them drops your credit score. Common sense would have one think that if a person has, say $100K, available credit that could be utilized in 5 minutes of buying they'd be a higher risk than someone that has one CC and a $15K limit.
There are several other reasons for the 3 major reporting companies to raise/lower your score. Average age of credit, total amount of credit available, revolving (store cards) history...and the list goes on. And most times the 3 companies aren't in total agreement either.
We use a CC to pay for almost everything, earning 2% back on everything we buy. If it doesn't bother merchants, I'll take it back for me.