I have a request for a cart/ stroller up in the marketplace right now. I have three different bags I use right now and it all depends on the situation. The NutSac is good enough for most of the 1-1 1/2 hour rounds that I play many times a week. The Crunch Box is good for most leagues or "serious" rounds with friends. I break out the Carolina for tournaments. However, I have been to several big courses where some kind of contraption would have been ideal. In fact, three of these courses actually have golf carts that can be rented.
Also, on those days I bring my kids along, lugging around their bags, toys, snacks, drinks, etc when they get tired does throw a lot of extra weight on me. My kids are not players, but I try to get them involved. This often means that at some point during the round they lose interest, which includes carrying their bags. A cart or stroller may enable them to act like this more, but at least it makes it easier for me to carry stuff around.
It is going to come down to "to each his/her own."