This perennial question does assume that the smart thing to do with intelligence is earn money, and to the extent that having money does free up your time, eventually, it could prove a good idea. However, if you sell all your time in exchange for money, putting off your thinking time, or your creative time, until you have 'enough', then maybe it doesn't seem such a good plan.
In the simple terms of IQ tests (whatever you think they actually measure) I score quite highly. I got a scholarship type pass to the 11+ exam (although that apparently had a bias towards boys), and on various self-testing scales I did pretty well (though such tests seem rather unreliable). When Test The Nation first happened I scored higher than anyone in the studio, and as high as the best on-line participant, but that test is not one recognised by MENSA, for instance. MENSA chooses people from the top 2% of the population, whichever test that gets measured by.
I only once met a group of MENSA members, and don't remember a particularly stimulating time, but I would not dismiss the possibility that not all members are too glum or serious for me. I appreciate that I might simply have been boring company for them. Who can tell?
I reckon I know quite a lot of smart people, particularly if we look at them through the filters of multiple types of intelligence (cf: Howard Gardner), a model which seems to correlate with the world far better, as those earlier tests do seem biased towards literacy and numeracy, in spite of a certain number of spatial awareness elements, and didn't appear to consider excellence in arts of sports (for instance), or maybe relationships, or the ability to communicate, as forms of intelligence.
Although I generally lean towards text-based learning myself (after decades of putting myself through the circus skills hoops, to encourage the other aspects of myself) I still veer away from books that sound like this:
"Despite the many specific disagreements that have marked the development of these theories of aesthetic and cultural postmodernism, their development has generally been contained within a horizon of consensus that has defined valid theories of postmodernism according to their deployment of methodological self-reflexivity, based (sometimes covertly) in the unconditional rejection of categories of totality, or totalization - a rejection that acts as a negative totalization itself."
This, from a professor of English - discussing the vivid and lucid writer William Burroughs, in "Wising Up The Marks" - a title that sounded sufficiently 'street' that I might find it amusing and enlightening.
No way could I study 'English' in such a context of abstractions and technical jargon (although I did find lighter patches in this book). That form of abstract, analytical study is what made Samuel Beckett sound unfunny, and Joyce 'difficult'.
The main problem for me, however, remains my dislike of tests. I don't like the experience of auditions, interviews, exams, tests or any of those events. Fear of failure, like everyone else (of course) plays a part in that - but also wanting to know who was so damned clever that they can set the tests.