He’s not a billionaire - I’m pretty sure he got X million, then decided that he had enough
He weighs in frequently on technology issues, his takes aren’t always ideal, but he’s a consistent advocate in an area he’s qualified to have an opinion in. He also helped found the EFF
From Wikipedia:
Wozniak has discussed his personal disdain for money and accumulating large amounts of wealth. He told Fortune magazine in 2017, “I didn’t want to be near money, because it could corrupt your values … I really didn’t want to be in that super ‘more than you could ever need’ category.” He also said that he only invests in things “close to his heart”. When Apple first went public in 1980, Wozniak offered $10 million of his own stock to early Apple employees, something Jobs refused to do.