1) Non-criminals also lie on the forms. Mainly because it's sometimes their only way to open a bank account (if they are deemed risky by an AML department), even if they have a legal source of income. This renders people who would otherwise not be criminals into criminals. Just recently, I came across a Tweet[0] from someone who will have to face this dilemma sooner or later.
2) It's a loophole for prosecution, as you admit yourself. It's meant to circumvent well established legal principles. For example, in AML cases, the burden of proof is reversed ("guilty until proven innocent"). It's used as a tool to punish people for crimes when the evidence is not sufficient. Is this really something we want?
[0] https://twitter.com/mikeinspace/status/1708719585556344993