It is unclear why this new model uses an older style ink cartridge. The reason could be that Canon had a remaining amount of parts that needed to be used up? This would make sense; as why dispose of perfectly usable parts when they can be used as part of a new production process.
As with all Canon cartridges, they can be refilled successfully; albeit without the ink monitor reading full again. The printers do allow you to continue printing but with low ink message. Dedicated Canon Pixma MP 230 refill kits are available from Premium Inks for £11.95 with free UK delivery.