> The US Department of Homeland Security and the Secret Service seized three accounts linked to Gox containing more than $5m. As research from The Genesis Block shows, the executed seizure warrant was dated 19th June, the day before Gox announced it would halt dollar withdrawals.

Not to mention they're a huge hacking target.

They can have it stolen. They can covert it to USD and spend it on operations.

It might be non-trivial to get large amounts of cold storage BTC up and running? This could be a good thing in the case of cold storage coins, for security reasons.

Some could have been stolen from a compromised server.

By taking it.