I have been trying for some time to create a custom board based on LilyGo ESP32. I found the schematic too complicated for me and that is why it took so long.

Now I came through a "tiny" SIM800C board Board was found here

Why in LilyGo board they use a so complicated, expensive way with so many extra components to do the "same" thing? Schematic is here on page 3.

I am not talking about Power which obviously is not included on the power board, neither speaker and mic.

But look at the Sim card, PWERKEY, GSM_RXD, GSM_TXD, S_DTR, S_RI The tiny board can be perfectly connected to the ESP32 using the TXD, RXD pins and work like a charm. Example is here without all those extra components.

What is the point? What am I missing?

Simcard is so complicated on the LilyGo while on the tiny board it looks so simply connected.

EDIT: I do understand that the small board cannot work alone and it needs the ESP32.. I am only wondering why it has so complicated schematic the sim800 part of the lilygo