Crypto is something you can "physically control" like gold (through being the only person who knows the key). Unlike gold it can't be physically stolen or confiscated. It can be easily authenticated (no counterfeiting). Unlike land or shares, or other paper assets it can't be transferred without the owner's consent. You can be 100% sure you actually do hold the asset.

In a stable, law-abiding society these advantages are a bit pointless, but enough people either see the future as unstable and lawless, or currently live in unstable and lawless places, that there is market demand for crypto as a store of value.