He didn't mention gambling but he said he is not going the direction of the bitcoin. He cited that he might loose investing in the coin. If we actually follow the trend in 2017, bitcoin suffered a great loss but managed to get back up. Elon Musk backing the coin earlier this year further helped the coin.
Wasn't he the first person who caused the fall in the worth of the cryptocurrency? Seriously, I believe that he's simply shouldn't add negative impact to the coins.