Poor special effects

Reportedly, Suicide Squad cost around $175 million to make, with a big chunk of the budget spent on creating the Enchantress and Incubus special effects. If this is true, why are the special effects so poorly executed?
The fight between Diablo and Incubus could have been the highlight of the movie. Maybe it was for many – it wasn’t for me. Leaving aside the fact that Diablo can actually fight Incubus (which is weird, since it isn’t established anywhere in the movie that they are on the same power-level), the special effects are the worst I’ve seen in a long time.
How long? Since last August. But hey! At least Suicide Squad is not a flop like Fant4stic…
