The RS485 chip is a unique solution and should be cost effective. However, The question is it better than opto-isolator with transzorbs, serial resistors and a RC circuit.

Second.
I have seen several robust RS485 circuits and most use transzorbs. Some use opto-isolation but, isolation in RS485 comms are used differently. As the transceiver are the ones that has direct connectivity to the outside inputs/wires. Typically the opto is after the transceiver, so when the transceiver dies the opto works to protect the rest of the board. In my situation, I need to try to make sure the transceiver does not die.