Pixel 5 is one of the few flagship phones that offers reverse wireless charging. However, Google is trying an interesting way to make this feature even more interesting. If you connect a USB-C cable, the Pixel 5 automatically turns on reverse wireless charging, making it a convenient Qi wireless charging mat.
Google also seems pretty smart about handling this automated feature. According to a support document, Battery Share is turned on for a short time only. If the phone detects that it is placed on top of another Qi-compatible device for charging, it works normally. Otherwise, it automatically shuts down Battery Share.
This does not mean that reverse wireless charging cannot be used when the phone is not connected to a power outlet. The Battery Share feature can be activated manually. It is even possible to do this without the charging adapter next to the user.
The automated reverse wireless charging feature looks like a smart feature. In this way, Pixel 5 turns into a useful wireless charger that can be carried anywhere easily.