Yes, wHIVE ERC20 tokens will be backed by HIVE. Alpha version (probably coming on Monday) will be centralized, so it will not as secure as coins like WETH that are fully managed by a smart contract, but more like SWAP.HIVE.
I have written a post about options to decentralize WHIVE (https://hive.blog/hive/@fbslo/decentralization-of-wrapped-hive-discussion).