He 'profited by' his experience/mistake. [=he learned something useful from his experience/mistake]
The book can be read with 'profit' by anyone who wants to understand how the system works.
We sold the house 'at a profit'. [=we made a profit when we sold our house]
(..) enemy out of Blackwood, Holmes. You would have made a valuable ally. How terrible is wisdom. when it brings no profit to the wise. We take power at noon. Then isn't anytime to waste then. Guess not? told you he'd be coming out of that top window soldier boy. (..)2009 Sherlock Holmes