tartan, it's great that you found the pain tolerable, but I don't think it is fair to extrapolate based only on your own experience, and declare that the pain must therefore be tolerable for everyone else. You are not the yardstick according to which all labours should be measured.
The suggestion that women only need to "relax" is unfair and condescending - it suggests that women are somehow to blame for their pain: if only they'd stayed more relaxed, they could have had a wonderful birth while chatting with the midwives and drinking tea. Maybe it works for some women, but for many others, despite starting labour in a calm and collected fashion, and fully aware that it will be painful (who isn't?), they end up needing pain relief or intervention. Being "relaxed" is not the be all and end all.
I also don't understand what you mean by "entirely worth it". Is it birthing that is worth it, or the pain? If birthing, that goes without saying; if the pain, what is the intrinsic value of pain?
I had the experience of giving birth with no pain relief, and of giving birth with an epidural, and I vastly preferred the epidural. Sometimes the "thing" that needs fixing is the pain - and once that is gone, you can have a very positive birthing experience. For my part I found it much easier to push when I didn't feel like my baby's 99th centile head was ripping my insides open.
You may think that "a lot of medical intervention makes giving birth harder than it should be." I hold the exact opposite view - that good intervention, such as efficient pain relief given at the right stage, makes giving birth easier than it otherwise is.