Because they serve different purposes (art Vs function). There is only one Mona Lisa. AI cannot replace the original's rarity. BTC serves function: A function that can be forked and improved upon. And improved upon it has been.
There are cryptos technologically faster, less traceable, and with more utility.
For now, BTC is mainstream and is being treated like a get rich quick scheme. When that pyramid scheme ends, BTC's prices crashes from a long way up.
It's wise to hedge against a possible crash.
When MySpace users saw Facebook, everyone deserted MySpace.
Think also Nokia -> Blackberry -> iPhone.
