How to understand the inverted state of the triode?

It is a triode anti-reverse connection, very common, this is to use the triode as a diode.

It seems wrong, the simulation result is not a diode.

In textbooks, the triode structure is often described as a PNP or NPN three-layer structure. It seems to be symmetrical, C pole and E pole can be used interchangeably.

but!

Today's transistors usually use diffusion technology, so:

The E pole is usually highly doped and thin, so the diode structure formed between the E pole and the B pole is similar to a Zener tube, and the reverse breakdown voltage is only about 7V.

The C pole is usually low doped and thick, so the diode formed between the C pole and the B pole is close to a normal diode, and the reverse breakdown voltage can be 100V or more.

Then!

After reverse connection, it is still a triode, but the current magnification of this triode is greatly reduced, maybe only 10 times.

And the breakdown voltage BVceo of this triode will drop to about 7V.

Is anti-reverse connection to protect the power supply?