To land any charge against us, the PL needs to show that we're guilty on the balance of probabilities. In other words, it's required to convince the Panel we're more likely to have acted as charged than not to have done so. Where the charges are especially serious, there's an additional requirement for the evidence to be particularly cogent.
Obviously, City's primary argument is that we haven't acted as charged. The audited accounts record the operations in question as legitimately performed and should be regarded as conclusive over whatever evidence the PL will produce to the contrary.
All well and good. But you never know for sure how the panel's going to respond to the evidence put before it. If you can make additional points to damage the credibility of their case, it's very much worth doing so.
Here, the point I assume we'll make is that the PL, in investigating and charging City, hasn't been acting as a good-faith regulator that's taking measures necessary to protect the sporting integrity of its competition. No, it's pursuing a witch hunt, egged on by our rivals, who have a disproportionate influence and a direct commercial interest in the PL punishing us.
If we can plant this seed in the minds of the members of the Panel, we make it correspondingly more difficult to believe that the PL's case as a whole meets the necessary standard of proof. After all, they're bound to be wondering why the PL would pursue a case against City if that case is as hopeless as we've publicly and vigorously alleged.
Should we present this argument persuasively and back it up with compelling evidence, we give them a reason for that. This is why it's important.