Yeah but when was the last time you've actually received a physical certificate? I've been trading for nearly 30 years and never once have I received one.
Anyway, there must be a record keeping (eg. clearing) for the cryto market, just as there is one for stock market, bond market and futures market. How else can you clear the trades?
Yes but the recordkeeping for crypto and the clearing of trades in crypto is a technology that totally relies on the computer network. And if that computer network does not exist anymore one day, the recordkeeping will completely collapse. If tomorrow, the computer network doesn't exist anymore, we can still trade and we can still have a record of the financial assets that we have today regardless of whether we have seen or received or have the physical certificates or not. The fact that we can have and have had them before makes all the difference.