[acdha]

They are legally required to know your identity and, I believe, report interest to the IRS. If they don’t check your government ID, they’ll be popular with organized crime.

Now, I’m sure banks also love that for data mining purposes but it’s not entirely without a valid reason.

[akira2501]

This is so the IRS can keep track of the $15.40 of interest I earned on savings?

What mechanism causes KYC/ID checks to make banks unusable to organized crime? What purpose was organized crime using banks for? Is the government unable to get search warrants for bank accounts?

These are probably not what most people would consider valid reasons. The problems created outweigh the value of the solution.

[zamadatix]

They're less interested in things like verifying your couple dollars of interest and more interested in things like money laundering and identifying assets to seize. Particularly setting money limits leads to what is known as "smurfing" to try to hide the activity. Not that I'm saying you must therefore consider these reasons good enough but throwing out strawment like a couple dollars interest is not highlighting what you'd like it to.