To split your coins
On BTC chain you have some coins in address (A), you send your coins to another address you own (B), and include a further special recipient address 3Bit1xA4apyzgmFNT2k8Pvnd6zb6TnwcTi to whom you send a few satoshis. (You have to use send to many option in your wallet, to send them at once).
Any transactions that contain this special address will be ignored by 2X miners.
Once this is successful, you will have your BTC in an address(B) you own.
IIUC, I would not employ this mechanism for my coins. The part that I have underlined seems to require full faith in what the miners will do. You have no a priori method of knowing whether that address will 'be ignored' by any miner.
Yes, it's a policy, miners could ignore the policy and include the transaction.