EOS is currently just an ERC-20 token on Ethereum platform. It's nothing different from making your own token on Waves platform with just few clicks. When EOS platform release next year you can use your ERC-20 token to register yourself as an owner of a piece of "EOS blockchain".

Think of the token as paper gold. Technically it's just a digital thingy. If EOS is real and not a scam you can claim a part of it. It's just a promise. The devs can just take the ETH and decide not to give any ERC-20 token holder anything. So the token is theoretically worthless.

We just have to trust the devs to keep their promise and they have economic incentive to do that.