Given that the entire plot involves someone chasing him to forcibly extract the data, it wouldn't seem it would offer more security than suitable crypto on a micro-sd card.
I might have misremembered though the wikipedia entry for the movie (I've never read the short story, so my comments here are about the movie) specifically says that one of the groups after him wants the data for themselves.
But if they just want to destroy the data, that just makes the security distinction even less relevant, as destroying his head with contents would solve the issue whether it's in his brain or on a foreign object in his head.
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