It’s a WiFi SoC that despite its ESP32 name contains a RISC-V core in place of the Tensilica core in the ESP32s we know, and uses the ESP8266 pin-out rather than that of its newer sibling.

Using the ESP32’s I2S peripheral in parallel mode makes it possible to shift data out in the correct format to drive the LCD without bit-banging IO pins and using up precious CPU time.