In the short story, 'The Bet' by Anton Chekhov, what did the banker and the lawyer gain?

In an argument about the morality of the death and life sentence, the young lawyer stated that both forms of punishment were equally immoral, but he would choose the life sentence. He reasoned that it was better to live in confinement, rather than not live at all. The banker challenged the lawyer's remarks, and a bet was placed. The banker offered 2 million to the lawyer if he could stay in solitary confinement for five years. The lawyer agreed but also raised the stakes to fifteen years on his part.
During his confinement, the lawyer studied different subjects. He improved his knowledge about the inner workings of the world and claimed that he was wiser based on what he had studied.

"Your books have given me wisdom. All that the unresting thought of man has created in the ages is compressed into a small compass in my brain. I know that I am wiser than all of you.

 
The banker read a letter by the lawyer stating his new found knowledge and wisdom. In his letter, the lawyer forfeited the sum of 2 million because he despised all earthly riches. The banker understood the point made by the lawyer, and it affected him deeply because he was struggling financially at the time. The banker learned that money was an illusion.

When the banker had read this he laid the page on the table, kissed the strange man on the head, and went out of the lodge, weeping. At no other time, even when he had lost heavily on the Stock Exchange, had he felt so great a contempt for himself.