Could you clarify for me if Bitkub is indeed a cryptocurrency wallet? I'm under the impression that it might be a trading platform or exchange, but I'm not entirely sure. If it is a wallet, could you explain some of its key features and how it compares to other popular wallets in the market? On the other hand, if it's not a wallet, what services does Bitkub primarily offer and how does it cater to the needs of cryptocurrency enthusiasts and investors? I'd appreciate any insights you can provide.