Exactly. If Bitcoin becomes centralized, then it would be more like fiat currency issued by a central authority. There would be no use for the Bitcoin blockchain, since people's funds would be subject to all the downsides inherent within government-issued currencies like the US Dollar. Therefore, what keeps Bitcoin alive is its decentralization. Due to such property, anyone can gain control over their own funds without worrying about confiscation, or negative events in the real world. Bitcoin is immune from politics, inflation, and external manipulation. Its success has been driven because of such factors, which I believe that it will experience constant demand over time.
Nevertheless, Bitcoin as a decentralized cryptocurrency would do just fine, to maintain itself as a store of value, and a safe-haven against real world assets/commodities. In case where you cannot receive funding in fiat currency (because of a government freezing your bank account), you can always count on Bitcoin since no one can stop you from transacting in it (even if its banned on a country) simply because of its decentralized nature. Just my opinion