10 years ago, the answer to that question would have obviously been: Any kind of crypto

(though I'm not advocating anybody puts their life savings into crypto now)

US dollar is guaranteed to lose at least 50% (lowball) of its value over the next the 10 years, most with this knowledge are choosing to protect wealth by investing in scarce assets.

Bitcoin is an easy choice for wealth preservation as the most scarce/liquid/desirable asset available to most humans.