Currencies have popular names like Yen, Dollar and standard names like JPY, USD.

XBT is not about renaming Bitcoin, but to agree on the unit compatible with legacy financial software and thinking of the rest of the world, so it helps adoption.

Traditional currencies are dividable by 100 (and not more), therefore virtually none of existing financial databases support currency columns with higher precision. This is why it is suggested that the standardized unit for those applications should be: 

        1 XBT = 100 satoshi 

that also leads to
       
        1 Bitcoin = 1 million XBT

The notation is handy since:

        1,234,567.89 XBT = 1.2 Bitcoin or 1,234mBTC.

It is XBT and BTC because BTC is actually taken by Buthan and X is reserved for supranational currencies.

No conspiracy kids. Just a practical solution. Nobody takes Bitcoin away from you.