It’s because it’s simply a good idea to diversify your reserve currency, especially if your currency is unstable.
SWIFT already handles a diversity of currencies including Renminbi, so that’s not what CIPS is about. Everyone knows what it’s about: an alternative to the imperial core’s transaction system.
The BANCOR idea is just wishful thinking, no one is migrating back to some kind of gold standard anytime soon.
Implying that BANCOR is anything like a gold standard only shows that you don’t have even a Wikipedia-level understanding of BANCOR.