Bottled water & k-cups are fundamentally about time & convenience.
Buy a pack of bottled water or disposable cups and you just avoided an entire workload of maintaining, tracking and washing a bunch of cups. Out and about and don't want to maintain your own personal water bottle, and don't want flavored water? You buy bottled water!
Same with k-cups. You don't have to maintain a grinder and bean bags, you don't have to wait for the drip coffee machine to finally finish, you don't need to boil water for crappy instant coffee with sediment, you don't have to clean any of these machines either. You just fill the machine with water and clean your mug and maybe descale the thing a couple of times a year.
Buy a pack of bottled water or disposable cups and you just avoided an entire workload of maintaining, tracking and washing a bunch of cups. Out and about and don't want to maintain your own personal water bottle, and don't want flavored water? You buy bottled water!
Same with k-cups. You don't have to maintain a grinder and bean bags, you don't have to wait for the drip coffee machine to finally finish, you don't need to boil water for crappy instant coffee with sediment, you don't have to clean any of these machines either. You just fill the machine with water and clean your mug and maybe descale the thing a couple of times a year.