No. Without internet, you cannot receive Google’s bi-weekly security updates. You must connect online occasionally. Offline installation does not block future online updates; it just skips the initial download.
Using the method above—downloading the .bin via a download manager, writing it with Rufus in DD mode, and installing without Wi-Fi—you can revive any aging 64-bit PC or Mac, completely offline.
Method 1: Create the 64-bit Installer Using the Chromebook Recovery Utility