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The special platform can do this by automatically converting the bitcoin to stablecoin but still delivers Bitcoin to the recipient. The recipient can then withdraw his Bitcoin at exactly $1000 or buy stuff with it. While buying stuff the conversion from stable-bitcoin to Bitcoin happens automatically without him even knowing.
People should choose whether to have stable or volatile Bitcoin.
Your idea is unclear for me. No cryptocurrencies are stable now; creating a stable currency is a very difficult task. Maybe stablecoin can be created through controlled emission (which counteracts price spikes), but then there will a problem of trust to those who control the emission. Probably, bitcoins will automatically become stable when their capitalization increases by 1000 times (more “heat capacity”), but this is a long time to wait.