When it would be more profitable to stay legitimate instead?
For example there was Stackcoin. Its dev had an IPO that raised 70 BTC. It had an interesting idea and screenshots were posted showing the concept being developed. Wouldn't it have been more profitable to just develop the coin instead?
Or the Sharexcoin exchange. A lot of development went into that site and the site was a fully functioning exchange which would have been a good long term investment for the site owner. But instead the owner decided to scam its users by closing the site and running off with its users' coins. I think he was later caught trying to sell 24 million QORA on Poloniex which they were able to identify and seize.
It doesn't make any sense.
The best way to understand why anyone would do anything is by first understanding that, "each and every action a person takes, he takes because he thinks it will make him feel better".