1
Can I import newly generated address to Bitcoin core with "importaddress" rescan false, for the watch only purpose?
why do I need to rescan if the address doesn't have any history?
Question: will it trigger the "walletnotify" if it receives new transaction on that address without rescanning.
2
why do I need to rescan if the address doesn't have any history?
It does not know it has no history until it completes the rescan.
You can either pass a false as extra argument (look up the importaddress documentation), or use the more powerful importmulti command with a recent birth time.
