Well, I think it's a dark side thing. Prolonging your life after you're dealt a mortal wound is unnatural.
Sion and Maul seem pretty similar in mentality so I think it works from that perspective.
After I posted it, it seemed to me that it's similar to what Plagueis was trying to achieve, which I find a bit ironic, especially considering
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the synchronicity of their respective deaths. Or in the case of Maul, "death."
I've also seen it suggested that Sidious had a hand in his survival and mind wipe, using Plagueis' ability to save others from death, which the Revenge of the Sith novel had already implied he used to save Anakin on Mustafar. Which we now know is not precisely the same as creating life, so it would work for Sidious to know how to save someone.