That would arguably create some of the worst perverse incentives, as far as financial crimes go.
Any two-bit governor could team up with some criminal, and make enough money to be set up for life against a pardon. Even worse if it's a president, as they could likely get off scot-free.
Trump could literally scam everyone and everyone, step down, receive a pardon from the VP, and happy days.
That’s exactly what it’s doing. As long as you misbehave in Washington DC or commit a crime not chargeable in a state or too complex to prosecute, you’re good.
For example, you could defraud suckers into buying a pump and dump memecoin. Elon has repeatedly demonstrated that nobody will prosecute, and POTUS is above the law for as long as he decides to stay in office.