It's primarily latency but bandwidth can also be an issue. Assuming you have a fast enough Internet connection (possibly not a safe assumption here in the U.S.

It's primarily latency but bandwidth can also be an issue. Assuming you have a fast enough Internet connection (possibly not a safe assumption here in the U.S.), imagine your PC or mobile device(s) decide to update themselves or just generally get 'chatty' while you're playing. I've had this create problems for relatively bandwidth-sipping VoIP sessions so I'd imagine it would be much worse for a game experience.