Maybe your client is guilty. Maybe it will be easy for the State to prove that your client is guilty. That is, if they can get their witnesses to show up.
There are all sorts of reasons that defense lawyers set cases for hearings and trials, not the least of which is that they expect(well… hope?) that a judge will suppress some or all of the evidence, or that a jury will find their client not guilty.
Occasionally a client will even volunteer this as the solution to their problems, “What are the chances that so-and-so won’t show up, and my case will be dismissed?”