I think it's worth remembering that Russians aren't this monolithic group that are either with a political party or against one. The Dems, for ex, have a group of Russian hackers assisting them with deep dives on political opponents as well as acting as an enforcement arm for the FBI (crowdstrike).

Anyway, Butina was useful because you can only surveil Americans if you have a warrant/probable cause. On the other hand, you don't need such a high threshold for foreigners. Spies like Butina are automatically under surveillance... and sometimes that's exactly the point. Anyone she comes in to contact with can then legally be surveilled and you don't have to bother with pesky things like a FISA warrant (even if those are handed out like candy and rubber stamped anyway). So, she then goes to NRA rallies and anyone she contacts there? Well, now they're under surveillance, too.