2-3 years is considered long-term? Damn. I know it's subjective but in my opinion the bare minimum of "long-term" should at least be like 6 years or so.
Many investors are recommending people to do to enter any project with the money they need, use the part of money you don't need it.
I don't think people should be recommending people to invest in a risky asset at all. This is the reason why I really never suggested buying bitcoin to anyone I know personally. I just talk about bitcoin sometimes, and it's completely up to them if they're interested enough to look it up and actually invest.