Ok. Then here's what I think.
Trump is well know for his vindictiveness and thirst for revenge. I'm sure we can agree on that. Trump has one real skill, he knows how to use the legal system to get what he wants and now that he's president he has near unlimited sway over the legal system (the attorney general) So, based on those facts here's the Occam's razor story.
Trump is looking for any reason, no matter what, to drag Comey into court
*. Even if for nothing else, to bleed him financially in a legal fight that will take months, perhaps years if appeals are considered.
One reason why Trump fired Bondi is that she wouldn't charge Comey with this obviously flimsy case.
By way of explanation - I have zero love for Comey. His timing of the investigation into Hilldog's email bullshit was specifically timed to influence the election against her. IIRC he even said he knew his timing of the announcement would in fact have political overtones. He said so in his book (source below)
https://www.theguardian.com/us-news/2018/apr/13/james-comey-book-hillary-clinton-email-investigation
*EDIT To get revenge for the Russiagate investigation.