I'm not an expert on automotive systems specifically, but in general with silicon level stuff like this when used in small, highly integrated systems, just having a PHY isn't nearly enough. Really, you want it to come baked into all the MCUs and MPUs your particular vertical uses so you don't need to waste time making your board designers wire up more shit and you can use the vendor library for your MCU instead of writing more shit. Most automotive microcontrollers come ready to go with a full CAN interface including all the libraries and such that you'd want, as well as dev boards that pin it out to whatever connector so you don't need to waste a board spin cycle creating an EDU.