One use case where this might be a problem is when you want all of your queries compiled at your application start time (using QueryProcessor::compile()). This is a speed/CPU load issue.
Please tell me I'm wrong it this is done automagically for modules stored in the database, but my impression is it doesn't happen until you call compile or execute (which calls compile).
I'm working in Java and plan to use Apache Commons Pool to store a bunch of sessions with associated start-time-compiled queries for the threads of my website requests. Can anyone see any problems with this approach?