So your argument against tracking and enforcing money laundering laws is that laws in general are silly because not everyone agrees with them?
Certain laws are truly silly, however. I am allowed to maintain that opinion. I may also be anti-authoritarian in general, and do not believe in the vast majority of consensual crimes.
I'd presume there is a deterrent as well as a direct effect on reducing money laundering; I'd expect to see more money laundering if there were no checks.
Quite how it would be measured is another question.