Many people have multiple addresses.
Many of these are lost.
But also....many people share addreses. And I dont mean exchanges here, I mean my family. Doesnt hold keys, but has bitcoin via myself.
Discussion
This is a good point. I have an address dedicated to friends who I've lots bets to, owe for fantasy football, yard games, etc. But they haven't committed to making a new wallet yet. So, I log who owns what in the wallet. Sure, I could make them a wallet, but I want them to have skin in the game to 'collect'. Until there, I probably have 6 people in one wallet.
But good to see the numbers go up, but wallet numbers can't be a real indication of users.
Its a ballpark. Glassnode estimates 25M direct key holders and exchange accounts estimate 200-250M indirect users.
It seems low but there are so many smaller currencies. Bitcoin has reached escape velocity.