Having Multi-Player games using Jingle doesn't mean all the commands, events and actions will be sent in XMPP Format through IQs.
Jingle can also be used to negotiate direct TCP or UDP ByteStreams which is the most suited for low latency Games like Shooting Games for instance:
<content creator='initiator' name='dukenukem'>
<payload-type id='1' type='controller'/>
So if you are looking forward to build Multiplayer Games, you may consider ejabberd or Openfire a ready to use platform for such.
This is an insight post, so please fell free to send question and ideas as comments.