It was a way to punish Eobard once and for all. No more letting him escape, not killing him one knowing somewhere out there was a time remnant.  It  turned him back into the man obsessed with the flash in a different light. It was impossible to erase all the harm Eobard had done from the timeline to change that much. But by grounding him in one point of time  in their reality, it ended the Reverse Flash. Leaving him what he was in originally as the  tour guide in the Flash Museum of his Era without a clear memory of his hatred. 

There was the idea that Eobard they hated was trapped eternally inside, as that version of himself praised The Flash. Never able to take control or emerge just tortured by the same sights.  Looking at the museum that celebrated The Flash, his team, and his family. Speaking their praises and supporting their legacy.

It was a relief to the family, but Thad remained conflicted.  " I'm happy, and  then I feel hollow about this.  He'll always be paying for what he did. Or what we did ended him if I really believe it.... We all closed that chapter in our lives... Just help me with these blank pages. And keep me from visiting him...."