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]
(..) I agree. - I'll go. - You can't! I have known Lord Walder since I was a girl. He would never harm me. Unless there was a profit in it. What do you want? It is a great pleasure to see you again after so many years, my lord. Oh, spare me. Your boy's too proud (..)2011 TvShow: Game of Thrones Title: Baelor Season: 1 Episode 9