They are politicians and can change their political approaches when they see a change will help them to gain benefit for their political career.
Trump and Biden are the same, their mindset on Bitcoin and cryptocurrency can change with time.
Trump changed so did Biden.
Trump changed a lot recent months than what he thought in 2019. <...>
You are right that we should not rely too much on these opinions, which are for political convenience and may change in the future if they believe that what suits them is something else. Anyway regarding bitcoin Trump would not be the first one who did not like bitcoin and happens to like it, plus I think he has seen a niche of votes from people concerned about privacy, which would be more generally Republican people, who do not trust so much the state and its CBDCs.