I find as I get older, my joints tend to float around in their sockets, much like a bag of bones. Especially in my back. And so one having set of muscles back there tensed-up, while another set is relaxed, can cause misalignment, pain, and eventual injury. Stretching can equalize the tension, increase blood flow, and put everything back into alignment, so that after a good night's sleep, and a few joints "popping", I'm as good as new. YMMV.
If you don't feel any benefit from stretching, don't do it, it's probably not helping. I can only assume that some people's joints don't float around in their sockets to the degree that mine do, everyone is a little different. But I know I'd probably be in a wheelchair or on crutches if I went 6 months with no stretching. Or at very least be in a world of severe pain and misaligned joints.
It's probably worth distinguishing sustained stretches, which I'm talking about, with simply "loosening up" which I think everyone does whether they realize it or not.