We use a business credit card only for the rewards part of it. We pay it off every week, yes I said week, not month. Our card gives us points that are basically equal to $1, that we can use as cash back, trade for gift cards, use for travel, etc.
Because cash back is considered income by the IRS and our accountant is very stick about it, we often trade the rewards for gift cards to places like Amazon or food places. We then use those cards to buy things we need or the sales team uses them to entertain local clients with drinks and or food.
We do have a business line of credit but business has been good and expansions have been able to be covered out of operating funds.
Having business credit allows you to expand if the right situation comes up. For example, we are in talks with a very large game manufacture that may require us to use the line of credit if they decide they want all servers at one time. We have it available if needed, otherwise it just sits there waiting to be used