This new format simply represents the information that something like MAME or some other emulator reads from a config file, like this: https://github.com/mamedev/mame/blob/master/hash/intv.xml
This new format is better, as it doesn’t have dependencies on a config file, new Intellivision homebrew can be created without needing config file updates. Not to mention it’s a PITA to have an FPGA have to parse an xml config file like this.