I agree that's why we better not take it seriously, on the contrary others is sure that his statement is very positive for crypto market for whatever reasons. And even his pro bitcoin supporters are now confused, lol. Trump doesn't look stupid tho, he is such a dumb loose cannon.
Based on what Trump have done so far in his career, his ultimate goal is financial benefits. Sure, he or his relatives have likely invested or might invest in crypto. There is an assumption that Trump tried to manipulate Bitcoin and crypto due to his lovely daughter, Ivanka.
https://www.ccn.com/news/why-ivanka-is-the-ticket-to-influencing-trump-on-bitcoin/2019/07/12/