yeah its a good question mate.
here is the answer to your question on bitdegree.com
Token vs Coin: learn the token and coin definitions & the differences between security token, utility token & equity token in this Token vs Coin guide.
www.bitdegree.org
so ADA coin is native to the cardano (ADA) blockchain, because it runs on its own blockchain its considered a coin, so Bitcoin, Bitcoin cash, Litecoin, Monero all run on their native blockchain.
Tokens usually run on someone elses blockchain, cardano still have yet to release smart contracts and apply DAPPs on their blockchain, but their is some hope this will come in the near future.
So there will be tokens being released on blockchains down the years and essenentially this is what differs between a coin and a token.
Ether is strange and even that article kind of contradicts what it says it is native to the ethereum blockchain so ether should be considred a coin but then also it states towards the end that ethereum can be considred a token so that can be left open for some interpretation.
Alot of tokens (ER20) have been built on the ethereum network, along with dapps that can be used in the real world that are being deployed on the ethereum blockchain.
Hope this clears some things up. The space is huge and i am learning every day as well!A