Stocks do not need buybacks or dividends. They are rights to control a share of a company, which earns (or potentially earns) money. That’s inherently valuable even without a stock market to determine a price. You control a machine, which makes things and earns money.
Crypto is only valuable, because others think so, too. You control a place inside a distributed list. Others think a place in exactly this list is valuable, while all the other lists are shitcoins.