Since the remaining Gnosia knows the Coroner is lying (since they know that the species of their scumbuddy), the remaining Gnosia may consider the Coroner anti-Crew (either an AC Cultist or a Bug). So you, as the lying Coroner, could make the remaining Gnosia trust you, at the cost of making everyone else distrust you if you admit to lying and reveal the true result. Potentially useful, but you'd have to weigh the pros and the cons.
EDIT: You don't have to ever reveal that the scumbuddy was Gnosia, by the way. If you say the scumbuddy was Human, and then somehow push the freeze onto the remaining Gnosia, the game ends automatically. So you can keep up the facade of the scumbuddy being Human as long as necessary.
EDIT2: I think this strategy can only work against the Gnosia if you aren't a confirmed Coroner, and if there is a realistic possibility of you fake-claiming the position. If everyone thinks you're the genuine Coroner, then when the Gnosia hears that their scumbuddy has been exonerated, they're just going to be confused. They know you're lying, yet they also know that you aren't looking out for their interest...so they don't know why you're lying. They won't trust you though, which is what I think is needed for EJ's tactic to work.
EDIT3: Note that this strategy may be a bad idea if there is a living Bug. The Crew may focus entirely on the Gnosia threat, thinking that the Gnosia is more powerful than they really are...and that they can worry about the Bug threat later. The Bug, meanwhile, can win if the remaining Gnosia accidentally outs themselves and gets frozen.