Now that I think about it... It could be this pump is the hackers buying bitcoin. Now the news is out and they are being hunted. They have to digitally hide their tracks and can with bitcoin/tumblers
I'm sure these hackers are well aware of bitcoin for laundering.
Most exchanges have to comply with KYC/AML laws. You could pump by buying on localbitcoins but it would be more expensive. The bigger advantage is keeping the loot, not laundering. Hiding it and moving it is where BTC really helps.
Tumblers would take a long time to mix that much scratch. You could just mix it as you needed it, a little at a time and be set for life.