Yeah, your own washcloths and towels are also a great way to make the hotel staff's lives easier. ♥
I actually got hooked on makeup wipes after cosplaying in Japan. The changing facilities tend to be pretty crappy over there. As in, "four square feet of carpeted floor" - most venues just designate the sort of room we would use to host panels as a "changing room", and everybody crowds in and sits on the floor to change. Usually costs money to get in, too.
So, yeah, without any access to running water or electrical sockets, the Japanese 'layers have to get creative, and wipes are quick and effective. I had to borrow one off a friendly stranger to de-black my eyebrows before going home, my first time (you're almost never allowed to leave the convention area in costume).
They're nice for quick costume changes even when you
do have your own hotel room/bathroom, though, and they save a lot of headache for the laundry staff.
