I agree that this change only complicates the process and probably doesn't stop them. Launderers are just going run the numbers (since drop rates are public), and at the scale they're operating at they can probably rely on expected values. If the new margins still work for them they'll just unlock boxes and sell the skins directly. And I'm inclined to think the margins will still work, since the market kind of naturally prices items around key costs.
Valve doesn't need to stop money laundering. They just need the money launderers to go elsewhere. (And they need the regulators to leave Valve alone.)
Financial regulation has caught up to most of the exchanges and it’s not always easy to get cash out of a system (and that’s not even mentioning loads of shadier exchanges near-guaranteed insolvency)
Random criminals are well advised not to trust their own judgement about crypto claims, nor their own prowess in operations security.
Keep in mind that eg lots of bitcoin exchanges have been hacked without any flaw in bitcoin itself. It's probably even easier to accidentally leak information, even if the underlying coin you are using doesn't.
(Of course if you want to liquidate to non-trivial amount of money, you're probably not interested in speculation)
If you like your job, your cost looks very different from doing an equally demanding job you hate. The emotional cost is real and can have long-term effects on your health.
Plus of course clicking stuff on your computer is something you can do in your time wherever you are as long as you have an Internet connection. Working for 1-2 hours at a gas station (or McDonald's or whatever) requires a fixed schedule and commuting, not to mention that you'd likely need to agree to a minimum number of working hours and are unable to just skip it whenever you want.
"Why don't you do this other form of unskilled labor for minimum wage instead" is a legitimate question when the current alternative is time consuming and they're struggling to make ends meet. Not so much when it's something they do for fun every now and then while already holding a job that pays above minimum wage.
the thing to remember here is that money launderers are looking to push a lot of volume. they care about the volume of clean money they can get, even if that means negative margins (you are "paying" for the service). i'm guessing market making in crates is not a very high volume kind of service but I might be wrong!
OTOH, since "worldwide fraud networks have recently shifted to using CS:GO keys to liquidate their gains" probably has at least some basis in reality, what's the story there? What other methods are criminals (presumably) shying away from now?
all of that is to say that you aren't going to stop money launderers by cutting liquidity, you do it by identifying their behaviors and blocking them based on that.