I2c looks simple in hardware, but complex in software, especially on the slave side. However, when you have a deep look at the I2c, the hardware is not that simple/cheap. Extra drivers are still needed for long distance communication and circuit protection. Also the value of pull-up resistor and capacitance has to be calculated depending on the number of nodes on the bus.

I would advice a beginner to use RS485 for its simplicity in software and flexibility in terms of distance. The only catch is its pricy driver.

Regards, Oliver