I wonder if he hid other profits in other crypto accounts. Or perhaps he viewed this as testing the waters and building a reputation before he scaled up.

It’s possible that he just enjoyed the thrill of doing crimes and getting fun money. During the first crypto-mining boom, my friend in corporate IT caught multiple people trying to use office electricity and networks to mine Bitcoin with hidden hardware. One person even tried to hide their mining machine above the drop ceiling tiles. They couldn’t have been making much money relative to their salary, but they liked the idea of being clever enough to get free money for themselves at the expense of someone else.