Is it possible to use the internet through another person’s local connection remotely?

Say an app allows one to use or access legally another person’s local Wi-Fi lists to connect to.

The remote agent uses the remote phone to connect to the internet from that device and then broadcast that quickly back to the agent.

This is not like a proxy but a bit different, no?

Is this not possibly more efficient since it bypasses the need for a local configuration, but instead just sort of screencasts another remote device from which you can harbor internet access from?