From this, it looks like Mueller plans to burn it all down. It looks as though he’s decided that everything with which this president* is involved is so irredeemably corrupt and lousy with dirty money that trying to split the difference between which corruption was involved with the campaign, and what dirty money financed it, is an impossible rat’s nest to untangle. So the easiest thing is to light a match and see what burns in what color flame.
It's hard for our legal system to take down a president. It's probably not so hard to take down his business (which the constitution should have already done, but, hey...)