Considering how much and how fast the price is rising, even hundreds of millions of dollars won't make a significant difference. Still, I think it's better to auction seized funds from illegal operations instead of dumping them on exchanges. Auctions can start around market price but actually push the price up, with some people having a desire to have those specific coins. I know it goes against fungibility of Bitcoin, but it could be better both for the price and for the US government: the price wouldn't be affected, and the US government would get more funds.