Stablecoins (payments or store of value) are likely the largest non-trading activity today with $123B market cap and $30B in daily volume. You'll see a lot of volume around staking crypto / running validators. Tokenized treasury bonds and other real-world-assets like carbon credits are getting up there, so is credit investing with companies like Maple / Credix / Centrifuge.

The long tail of activities includes things like DAOs (remember Constitution DAO?), prediction markets, internet infrastructure (VPNs, Arweave, ENS), synthetic assets, and more.

Since this is in the context of tracing illicit funding, two items to throw in the pile for consideration:

1. Trading which is actually part of the laundering/tumbling process, to disguise the path of coins from initial shady transactions.

2. "Wash trading" (yet another cleaning-related term) where a self-trade is disguised as a real one in order to manipulate the market.

The best use case is store of wealth and transfer of value in countries where institutions are corrupted.

Here is what an Argentinian has to say on HackerNews

https://news.ycombinator.com/item?id=35956148

Speculation