LCD shield P8 "SPI commands"?

How is the use of P8 different from P0 with the LCD shield? It is documented as “SPI commands”. What sort of commands are issued via P8 as opposed to simply being sent as SPI data over P0 (MOSI)?

Thanks.

It should be “command”, this pin is low for command and high for data. It’s just how the LCD driver chip works.