The answer to your question is the focus of the other prong of the FBI investigation. In a nutshell Hillary was hiding the pay-to-play scheme she and slick used to funnel two billion tax free dollars into their foundations that they obtained through donations that were really bribes. In return Hillary used the office of the SoS to “help” the donors with any problems they may have had here or abroad.
Ericsson sold electronics equipment to Iran that could be used to track opposition sources. Definitely breaking the embargo, but a huge “investment” in a speech by Bill Clinton (the largest fee to date) and all problems were solved.
” In return Hillary used the office of the SoS to “help” the donors with any problems they may have had here or abroad”
That may have been part of it but I do not think that is what the intelligence agencies and FBI are primarily interested in. Their focus is of course her dissemination of classified information and documents to foreign entities and corresponding donations made to her foundation from known front organizations of foreign countries.
This is a classic case of espionage, in the vein of Jonathan Pollard.