I use BECU as my main checking account. I have a line of credit there, and was able to set it up as an automatic overdraft on the checking account. It's a safety net -- if I ever miscalculate instead of overdrawing my account and/or bouncing a payment, it'll just draw from the line of credit and I'll pay a small amount of interest and not a terrible rate. Then I set up all my credit cards to auto-pay full balance from that account. So long as "full balance" isn't greater than the limit on the credit line I don't have to worry about that.
In practice I always make sure there's enough money to cover the bills, and I haven't had a balance on that line of credit in over a year, but it's huge peace of mind to know I have that safety net.
A lot of places will give you a line of credit but only a few let you hook it up as an overdraft like BECU does.
Amex BCE $40k || BoA Travel $5k || FirstTech MC $5k || BECU PLoC $10k || Discover Miles $27.7k || CITI DC $27.5k || CHASE Amazon $12.5k || BoA Premium Rewards $31k || BoA Cash Rewards 26k // AU on DW's Costco Visa $12k