I've been following this stuff lightly for a few years and if you look at the pace of technological progression, especially when it comes to things like mapping the human genome, it's easy to think that in 50 years the face of medicine will have undergone tremendous change.
It was hard for me, because there's a non-zero chance that I'm going to lose a couple of years with my Dad because of this. I'm glad he did it though, because someone else's Dad might get to live because of it.
I assume you're undergoing counseling before the operation. If you decide you don't want to go through with it that's totally fine - the fact that you're considering it at all is amazing.
Recent progress with the thymus is an unexpected gift. It is expected that achieving the same with other organs is going to be pretty challenging, lacking such a short cut. Hence the need to speed things up: advocacy and alliances and research prizes.
I'm healthy, I only need one, and like I said, I figure by the time I actually need one we'll be able to grow one -- but I suspect it won't actually come to that.
In that light, it doesn't seem all that altruistic.