Yes, this is a valid way of considering life. I'm personally not that into travel or starting a family, so I just replace the "might as well have just" to fit my own interests.
I think starting your own project or startup can fall into that category, too. It can be very intrinsically fun and rewarding, and the idea is to do stuff that's intrinsically fun and rewarding while we're still alive, I think. Writing 2.0 of BigCorp's latest TPS management app carries none of that, and so it seems like a complete waste in the grand scheme of life.
Another option is to do things that really will have a significant positive impact on people's lives post-death, and despite the fact that you won't be able to see, feel, or appreciate the impact you caused after you die, it will still feel very worthwhile for the entire duration that you're still alive. Like helping fight global hunger or disease, for example. You'll forget that TPS 2.0 app a few days after you've quit that job probably, but if you quit a non-profit helping fight hunger and you made something that actually tangibly helped, you'll probably think about that your whole life.