Originally posted on 11/01/2019:
For the sports bettors, Blockchain acts as an intermediary to keep the Bitcoin "clean". Coinbase and Gemini prohibit using their platform for the purposes of facilitating online gambling so you risk your account being closed if they trace the Bitcoin being sent/received from an offshore book. Blockchain makes that harder to track that by acting as an intermediary wallet so it's not going directly to/from a book.
Also, you hold the private keys to your Blockchain wallet. If you have your coins stored on Blockchain, it's the equivalent to having your money held in a bank; you risk losing those funds if the bank fails. With a wallet like Blockchain, you're in control of the Bitcoin so there's no worries of losing Bitcoin if an exchange fails. However, you're also responsible for the security of your wallet.