The purpose of the spying was to gain political intelligence for the benefit of Clinton by the political appointees of the Intelligence Community. Who did these people report to? President OBAMA! But when Clinton lost it morphed into a coup to remove Trump. Admiral Mike Rogers blew the whistle or Hillary would be President today, banana republic style.
From the evidence presented by Bongino and others, it goes a lot further than merely providing intel to Hillary. In fact there's not much Hillary would be able to do with the information gathered.
Before the election the intent of the spying appears to be to provide October surprise material. That's why there were stories planted by Steele in friendly media, but the stories were essentially created by the spies.
After the election it morphed into a coup as you suggested. But again, not to benefit Hillary as nobody really cared about her, but to stop Trump in whatever way they could, investigation, impeachment, etc.