A degree simplifies the cognitive resources needed to gain trust. Normally, gaining trust requires a lot of time. As a freelancer, it took me two years of very low-income work and repeatedly taking small jobs before I got my first real contract, simply because I didn't have a good degree.
But if you have a degree, you can skip that starting line quickly. I've done over 400 small jobs—work for college students, professors, and business owners. 80% of those were won with the lowest bid. And because I took those low-bid jobs, I eventually landed fairly well-paying contracts (about 35 of them) where I even drafted the contracts myself.
Moreover, while they say you can learn without a degree, it's much harder.
Why? Because a degree provides guidance through a curriculum. When you're just starting out, you don't even know what you need to learn. You have to ask around and figure it out piece by piece. A degree, even if you don't study properly, at least gives you the keywords to search for. Without a degree, you don't even know what it is you're trying to do.
I don't have a computer science degree, nor did I attend a good university. That's why it took an enormous amount of time to generate income from computer-related work. And even then, the vast majority of jobs paid below minimum wage, if anything at all.