It's mainly a privacy feature. Those addresses are separated into 2 which are the receiving addresses and change addresses. Anytime you hit the receive button on your wallet you are given a receiving address (a new one almost every time). And when you intend to send, those change addresses are used to consolidate funds so they can't be traced easily. So it's like you use different addresses anytime you send or receive coins.
The HD wallet have become the standard for modern Bitcoin wallet. Even elite wallet are integrating the use of BIP32, BIP39, and BIP44 standard into their new version, as it's part of what every HD wallet uses. I think, it stems across privacy, it boost the structure and security too of the wallets. From the security point of view, the HD wallets generates all keys from a single seed, making backup and recovery safer, it also reduce the resuse of address which protects the users identity and transaction history.