Well, I am the loner who voted for return of premium...which is what I signed up for 7 years ago after giving it a significant amount of thought.
1. It's quite easy to say "Just take the difference in premium every year and save/invest it". However, what guarantee do you have about what kind of return you can expect over the 30 years? None really. The return of premium guarantees the return you'll get, and it will be tax free.
2. It is a form of forced savings. If you choose the straight term policy without return of premium, will you have the discipline to put away the extra amount? Some will, most won't.
3. A few years in, the policy does begin to accrue cash value which will accelerate as time goes by. After some time, should there be a need to terminate the policy, some amount would get refunded. That's not a reason I decided in favor of this policy, but it is a feature.
4. I'm an extremely healthy individual and I fully expect to have the premiums returned to me at the end. Of course it is a calculated risk - me vs. my longevity. If I die and don't make it, well, I ended out purchasing a somewhat expensive life insurance policy. However, do I really care at that point? The policy is still going to pay off to my beneficiaries.
5. At the time, I did read up extensively on the product, scoured every article I could find on the topic (both pro and con), and liked/trusted the insurer offering it (ING, which is now Voya).
6. Over time, life expectancy has been increasing. Premiums for ROP policies have generally been going up, and fewer insurers are offering it as an option today versus a few years ago. My interpretation is that in general, insurers don't want to issue these policies because it is not very profitable to them - i.e. the insureds are getting their premiums returned at the end of the term.