It's an older question, but I'll bite. If I change RE to code, or cook or dance:
I would like to know in what cases would one want to dance to music
demonstrates how your question makes very little sense. to stay meta, people dance for the fun, or to appeal to other who like dancing, but both of those are internally motivated events.
Your question reads like, what your really saying is "does it pay good" and "what do I need to learn to get paid well".
Which also get asked of coding, and dancing. Coders as a general rule get paid well, where dancers don't, and it quite easy to see some can/cannot dance well. Where coding is more abstract. But still if your asking should I be a lawyer because those that do well, get paid lots, you also have to look at those who don't do well, and don't get paid well.
So back to RE, most people I know RE because they want to change something to work the way they want. Be that, without paying for it (cracking licensing) or add features, or removing "features". Thus have some form of internal motivation already.
This drives them past the painful part of learning part. Once you make it to the other side you start asking questions of "when I do X, Y occurs and I expected Z" now that a great question to ask imho.
The questions of the nature of 'how do I start RE' are worthless IMHO again, as those are answered many times already, and if you have a real problem to solve, you'll be able to find the more focused answers to get you past the hard part again.
This is sort of career related
like dancing/coding/RE when you are good work finds you, you get good by having skill/drive/reasons to RE. Thus questions on careers are almost pointless also IMHO, unless it is like "I've does some crazy stuff over here, now how do I get a job".