Hub is a common English word for a centre of activity, from transport to software. After BTC and wallet, it describes a meeting point: a site where users compare wallets, find help or manage several of them together. All three parts are short and widely understood, so the name works across languages and is easy to remember after hearing it once. The .com ending gives it the international default for a platform with users in many countries.
Among the Wallet & Storage bundle names, this one plays the role of the meeting place. On its own it suits an independent wallet directory with reviews and feature tables, a portfolio dashboard reading several watch-only wallets, a help forum and knowledge base, or a resource for developers integrating bitcoin wallets into their applications.