The machines' primary goal is to purify water and make it safe for drinking and other purposes. That said, they both work in really different ways. Whereas a water filter works by filtering out impurities like bacteria and protozoa from your drink, a water purifier goes a step ahead. It removes even viruses and some bacteria that might've escaped the traditional filtration. Purifiers are by design more expensive than a traditional filter, but that added expense is well worth the consistency and the lack of odor or taste in the purified water. Sure it is not as portable as your traditional filter, but it is safer, and when it comes to the long term, your goal should be to get as much safe water as you can.