If the sum total of the wealth you are trying to hide is a in the thousands, you aren't who the government is concerned about. At least, not enough for policy changes. So, while cash is likely far more prevalently use in crime, you're talking about the huge long tail of low level drug dealers and smugglers, not the oligarchs and money launderers.

Deposited/electronic money tends to be necessary when you hit a million plus. At that point cash sucks and is super risky to hold.