Anyone can create a token named 'Bitcoin' on a blockchain like Ethereum or BNB using smart contracts. But that's a different kind of scam. But the fake Bitcoin that I want to talk about, is actually created by some exchanges themselves!
Recently i came across a project that bears similar name to an already existing / successful project, but I have come to understand that there are lot of scams now in the crypto space which is why every crypto enthusiasts should trade cautiously. Any project can archive a great success even without creating their token similar to an existing successful project like BNB, eth and BTC, these projects just have to add funds into their token if they want to make success.
Let me tell you. Bitcoin has a limited supply - only 21 million. Moreover, with the rise in popularity of BTC and the fear of hacking on various exchanges, more people than ever have started keeping Bitcoins in their wallets.
Exchange is not a safe place to store Bitcoin or crypto asset unless it's a day trader or a future trader but if an investor really plans to hold his/her crypto asset for long, they must not store it on an exchange instead a cold wallet is safer. Asset may be totally lost once exchange is hacked.