I am confused as to how a crowdsale works. If in a crowdsale, people give their Ethereum to a new coin to be entered in a smart contract. Doesn't that mean that the receiving end of the contract (once the new coin goes live or whatever) needs to also be an ERC-20 public address?
What if the new target coin you are trying to sell, uses say a whole different protocol running on completely different computers, using the SHA3-512 hashing algorithm to sign keys in a completely different elliptic curve?
What power or validity would the ERC-20 tokens entered in smart contracts have over this new network the tokens are to be exchanged for?
So why then can a coin like Nimiq have a token sale of "NET" (ERC-20) and then later be activated to the final target coin Nimiq, and the NET tokens be left useless on the eth blockchain?