I2C is fine for sensors and other low-bandwidth devices, but inappropriate for displays and other high-bandwidth devices.

When used with those kits, you'd use the QWIIC/whatever connector for all the sensors and other low-bandwidth things like I2C is meant for, while the display would be connected with SPI.

(I2C isn't more plug and play than SPI though, and a preterminated plug shouldn't be a big deal.)