The phablet-network tool currently requires NetworkManager and wifi on the host in order to work, but not all phablet developers use NM. This causes the tool to fail when the host uses ethernet, or when the host uses some other network management system, or when the host uses a different wireless network than the device (5Ghz vs 2.4Ghz, for example). It also fails if the user doesn't have sudo access, or if they have sudo but phablet-network is wrapped in a script with no terminal input.
In short, it tends to fail in several cases because it assumes a lot about the network configuration. But we don't need to assume, we can simply configure and make sure it will always be correct. And perhaps fall back on the old NM automatic method when no configuration is available.
I linked a patch to fix this issue. It also fixes the issue in other tools which rely on phablet-network, such as the automated sanity testing suite, which would otherwise need their own patches or workarounds.