While on my road bike the clock is ticking for how long I can be comfortable. A few hours at most and then I have problems, maybe big problems. It takes me 6-8 hours to do a century, and around 16 to do a double century. The only way I can still be sane at the end of 16 hours is to use my recumbent. After 16 hours on my recumbent I am still have absolutely no discomfort, let alone pain, in my back.
To answer your question, yes, I ride a recumbent because I have a bad back (and hips), but only because I do some longer rides. My training rides are 35 to 65 miles, which can be done comfortably on my road bike.
It doesn't make sense to me to be in a lot of pain when riding my bike, even when doing long distances. That's not the point.