Therefor,  it could only be used to save us personally in future's economy only if we invest in it and hoping for its return in few years later if it is go smooth.
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Bitcoin whitepaper does not directly tell that its purpose is to replace dollars or fiat currency.  It aims to remove the third party from the transactions where a person can send his money directly to other people removing extra fees.  It also aims to have financial sovereignty wherein the holder will have full control of his fund.  So its purpose is privacy, decentralization, borderless transfer, and removal of the third-party intermediary institution to reduce the cost of transfers but never to be a replacement for fiat.  It can be a good alternative if the network congestion is not an issue.

As for whether Bitcoin can save us, I don't think it can directly, since whether Bitcoin will be a positive thing for the holder is dependent on how the holder uses his Bitcoin.