Wrapped bitcoin is actually a token that mirror's the values of bitcoin and is interoperable with decentralized applications built on the Ethereum network. Wrapped bitcoin actually tracks the value of real bitcoin, this means that each tokens value have one to one relationship with bitcoin
So if you want to keep a store of value,bit coin is a good choice.
However, If your looking to use your tokens for DeFi transactions, or if your interested in dapps,wrapped bitcoin might be better for you.
You can also convert your wrapped bitcoin into bitcoin by just clicking the unwrap inside your wrapped bitcoin wallet.
There's no such decentralized in Ethereum network, it's centralized and Vitalik Butterin has full control over the network. If it's decentralized, we wouldn't see any news hacker can rob users money.
Wrapped Bitcoin doesn't have any value, they just following Bitcoin price.
It's true you can convert your WBTC to BTC, but it's depends on the WBTC's team if they want to convert it or not. Which mean if they turn to be scam, you don't have any way to convert it since they wouldn't want to convert your shitcoin (WBTC) to BTC.