I think it's very strange to frame this as a good or evil question. Both scenarios you write about seem to be fairly value neutral, in fact in many cultures the second one (that you seem to be saying is good) would be seen as tending toward more irresponsibility and morally worse than the first.
But yes, I've done it and my opinion is that really the best thing is to follow a more natural course with your working life, taking advantages that present themselves in the course of your work and exploring avenues of interest as they become available rather than making arbitrary decisions to change course or jump ship and try something else. But that's just my own experience, changing careers midstream for me was a huge setback in terms of where I was in life, almost like starting again from scratch even though I was doing it for the reasons you seem to be talking about, in the end that seemed to be a very self-indulgent thing to do and maybe fell into the class of an evil act in that it robbed the world of the potential good that I could do with the experience and professionalism I brought to my previous career.
I think there is something of a false dilemma here sometimes, and there isn't really a choice to be made, in the end a job is a job ( within reason). Often it's more of an illusion generated by the self help industry and pop psychology boosters glorifying the follow your dream type of tropes.