Why Top Developers Love Fixed Pricing

I'm curious to hear experienced developers' opinions on this. Is it true that fixed pricing is better for both sides, clients and freelance developers?

Here's the part I related to: "Freelancers rarely prefer a fixed price payment unless the it’s significantly higher than market rate. That’s because they’ve been burned by scope creep or unreasonable clients so they protect themselves by accepting hourly payment." (emphasis mine)

So how does a freelance developer with fixed pricing protect against scope creep, "unreasonable" clients, or unexpected things that take up more time than estimated? Sometimes, the jobs are so customized and varied, that it's hard to make any accurate estimate, even after planning in detail.