When you identify the primary reason why corporations and governments never built built a centralized smart contract platform that's general purpose, open source, cross-border and uncensored, then you will know why decentralization is essential.
Don't get me wrong, the decentralization is important. I'd rather the network infrastructure of an expansive, public, general purpose computing network be decentralized. But to be useful in the first place you need important, interoperable applications running on it.