I've heard that I can get a lower interest rate with a secured line of credit. If I qualify for a secured line of credit, why would I still want to use an unsecured line of credit?
A secured line of credit yields a lower interest rate because if you default on it, the lender simply has you on the hook with whatever you used to secure the line of credit. i.e. if you have a HELOC and you default, they'll foreclose on you and take your house. An unsecured line of credit doesn't have the same type of clout for taking your stuff.
In short, a secured line of credit has a lower interest rate because it's higher risk for you and lower risk for the lender.