close to? sounds exactly like money laundering, since people who can move money legitimately wouldn’t do so through a relatively risky instrument like bitcoin. tax evasion is a likely entry-level reason, but often coupled with other sketchy illegalities.
The pseudo-anonymous nature of Bitcoin makes it easier to hide transactions. It’s for example why online games that let you cash money out (or have rampant RMT) have issues with money laundering and credit card fraud.
