JJ, Yes, there is strange logic in doing so! IFR aircraft are mandated to have a transponder. VFR aircraft probably won't go IFR, they might even stay grounded if the weather is remotely poor.
Use TCAS, get a LARS service and avoid the madding crowds, especially if you can get above overcast cloud. Just beware below 3,000 feet for the bloke coming the other way in cloud at the same altitude, without his transponder on, not talking, no LARS....