[magduf]

The problem with the infuser is that there's only one of them, unlike regular mugs where I have a whole bunch of them because they're practically free (they're a common gift item, after all). The infuser set-up is expensive, so I'm not going to buy 5 of them so I make tea frequently with no cleaning, so I need to hand-wash it. Regular mugs aren't like this: I can just use them and toss them in the dishwasher and get another one when I want another hot drink. And you're right, it's not a huge amount of time to hand-wash, maybe about a minute or so, but it's still a lot more than the utterly trivial amount of time it takes to put a mug in a dishwasher.