circuitbasics.com talks about the I2C protocol, it’s use and it’s advantages and disadvantages.
I2C combines the best features of SPI and UARTs. With I2C, you can connect multiple slaves to a single master (like SPI) and you can have multiple masters controlling single, or multiple slaves. This is really useful when you want to have more than one microcontrollers logging data to a single memory card or displaying text to a single LCD.
Basics of the I2C Communication Protocol – [Link]