You can look at just the first step, pretend that's the only step, and ask if it's worth your time. If so, go for it!

Um... no, I don't think this quite suffices. Not every step needs to have terminal value, or even affective instrumental value. They tend to, because it feels good to achieve measurable successes on a decent plan towards things you value.

But, well, I'll crack some eggs and put them in the pan, without expecting any intrinsic return from cracking eggs. On the contrary - it costs me eggs!

Still, I think you're hinting at a good point - from a granularized breakdown of a long task, you can guage whether you'll be motivated to finish by how long you go between really satisfying goals. Thus, I'll not even try to learn how to draw, because little but the very best visual art effects me noticably. However, I am learning to play the piano, because playing even simple songs is a pretty awesome experience for me.