Nobody likes to have their image used without receiving some $$
This really doesn't seem to be about money for him. This is likely just fraudsters using someone elses image and brand to scam by luring others into a false sense of security, which anyone wouldn't like, not to mention it tarnishes their name/brand/image so that's why they'll sue. It seems these sorts of scammers have been using quite a lot of famous faces to try sucker people into scams. I remember them using another celebrity to do so a few months ago: https://blog.moneysavingexpert.com/2018/03/martin-lewis-spread-word-dont-believe-scam-bitcoin-code-bitcoin-trading-ads/