He's a well-known/richest man in the world so he can use his clout whenever he wants, knowing that he's a fan of crypto (Dogecoin to be specific) will really create a huge impact to the crypto despite knowing that DOGE was a meme-coin. He's an inventor as well and I think that's one of the reason why he's supporting cryptocurrency technology. Soon enough I think Elon will make collaborations with top tier exchanges like Binance, Coinbase, KuCoin or even DEX's like Uniswap & Sushiswap and will accept crypto transactions when buying Tesla Model cars via BTC & ETH.