Hourly rates may not sound like a good bargain to a customer, though. If I contract with you for hourly work, how do I know you did those hours, how can they be documented/verified? And the more an hour costs, the more a customer worries about how hard you're working.
As someone who wants a story or (e.g.) 10K words delivered on a topic by a given date, I'm pretty sure I'd want to pay for the deliverable rather than for the time it took you to get it ready. The delivered product verifies itself vs unseen-by-me hours of maybe brow-sweating labor or maybe half of it spent looking out a window.
I guess it's good to have an hourly rate in hand if someone insisted on paying that way. However, if I were hiring out as a writer, I think I'd discourage a customer from that route. Personally, I think I'd feel better & not be questioning myself about whether I really worked hard enough each hour or not.