It is unstoppable, permissionless and pseudomic. All but the last is indeed this criminals dream.

But cash isn't pseudonomic, it's actually anonymous. It's even (practically) untracable. Cash is also unstoppable and permissionless. So it's far more a criminal's dream. Cash, however, isn't easy to transfer, especially larger values. It gets harder even if that transfer is internationally. Bitcoin solves that.

Bitcoin's upside of being very easy to transfer, sometimes outweigh its downside of being hard to launder, being tracable. But let's stop the myth that it's so much better than all existing systems to move criminal assets around, because it's not. It's complementary, not a holy grail. It really has a lot of weaknesses, especially to criminals' needs.

What is making you think criminals are scared of pseudonyms, or that pseudonyms don’t provide all the real and practical benefits of anonymity most of the time? It’s not a myth that a lot of crime involves BTC right now, it’s a fact, regardless of the theoretical underpinnings or hypothetical weaknesses.

Cash comes with serial numbers, and occasionally gets traced. It’s about as effective as tracing pseudonyms, most of the time.

pseudonyms are fine until the moment they can be linked to real identities.

At which point, because of the public, mathematical provable, ledger, the pseudonyms become concrete evidence, often in a "viral" way, i.e. through transactions a pseudonym can be linked to other pseudonyms and events.

In crypto, pseudonyms are a real and high risk threat. Not all, e.g. Monero internally "launders the coins" for you (technically not at all correct term, but you get the point...) so diminishes that risk. But even there, its there.

Edit: and while cash comes with serial numbers that can be used to trace transactions, crypto is only serial numbers that are precisely there to trace all transactions publically.