Aside from that, though... I think it's just that it feels like an additional step. You want to get going -- especially if you're the sort of person who moves quickly through airports -- and now you're just waiting as the lounge fills up. After a long international flight, you don't want to be sitting and waiting.
I won't be sorry to see the mobile lounges go. They were a clever idea at the time, but they're hardly "lounges" these days. They're just buses, at a time when you really, really don't want to be taking a bus.
Somewhat OT, but I just realized I've never flown internationally from Dulles. I've flown internationally a fair amount, and I've flown from Dulles a lot, but never the two together.
Less OT, everything I wrote was for domestic flights.
Yeah they're definitely just buses that can open on each end at this point. They aspired to be lounges and they kind of convey (ha) what could have been. An actual automated mobile lounge isn't that crazy, right? Automation+batter power does make it more appealing.