Former LE Anon responding. Worked for a major metro PD with more than one major interstate passing thru.
LE generally takes street-level busts as they can find them, that's really the distro side though. For the money/drug flow ( actual pipeline work) the focus is on the money. There's both selfish and good reasons. Selfish is obvious. The goid is that loss of drugs due to seizure is expected (and DOES happen) but taking the money is where the pain happens. That's what the dealers want.
People who lose money get desperate and are moar likely to flip out of fear for their lives, and sometimes turn into useful informants.
It's a dirty business for everyone, anon. Like Churchill not warning a town before it got bombed in WW2, occasionally hard choices have to be made.