Barriers to using the feature are not particularly high. Google officially requires Chrome OS 70, Android 7.1, a tethering data plan, and the same Google Account on both devices. This can change with third-party phones in the mix, but this is a positive sign.
This does not seem to be universally accessible and you may need to enable a flag (chrome: // flags / # instant-tethering) to work. It's also unlikely that this will reach a stable version of Chrome OS for a while. However, it may be very important if you like the thought of a connected Chromebook and you do not want to jump through the hoops just to stay online.