What is the purpose of using SPI versus I2C? The most compelling reason to use SPI in place of I2C is that you get faster serial communications speeds, and full duplex at that. The faster speeds are particularly useful for driving graphical displays. A bus clock speed measuring up to a few (3) megahertz can easily drive a 640 x 480 x 8 display… with one refresh per second. With bus speed as the bottleneck, you can trade for high refresh rates at the expense of lower resolution and color depth.
20191217/https://en.wikipedia.org/wiki/Serial_Peripheral_Interface