MAVLink messages through other types of buses?

Hello. I am getting started on using MAVLink messages to send commands from a companion computer to a flight management unit. I looked at the examples and they are either using UART or UDP. I am wondering if someone has used other buses such as I2C. Also, please kindly let me know if there are reasons why not using other types of buses. Thanks in advance!

MAVLink over serial has worked very well in the past. To me the the question is what advantage you would get from using I2C?

I am pretty new to PX4 and MAVLink so I am just try to explore different options here. The flight management unit board I am using has limited number of UART ports and are currently for other uses. And I have I2C ports available and that’s why I am wondering if I could use I2C for MAVLink communication…

Do you think using I2C for this could be much more complex? Or are there other disadvantages with it?