1. Crypto-assets like Bitcoin/Ethereum/Steller/Ripple, etc, are created simply by typing some numbers into a piece of software. There's no underlying value, it's a number in a database.
2. Stocks have measurable value, https://en.wikipedia.org/wiki/Price%E2%80%93earnings_ratio
3. Anytime someone sells a Bitcoin or whatevercoin it requires a buyer. Similar to baseball cards, beanie babies, or other artifitially scarce yet easy to produce asset, the market is subject to supply and demand. In the case of cryptocoins, the supply is created and distributed to a small group of users who horde it, in the hope that new users will come in and purchase the coins for more than it cost to create them. This is a hallmark of a typical pyramid scam, which collapses once no more investors can be found, leaving the late adopters holding now worthless "coins".
4. Stocks in Amazon and businesses grant you legal rights, and if the company goes bankrupt you are entitled to compensation from their assets.