Even though there was no specific need to make Venom huge, because he didn’t have a smaller Spider-Man to fight in this movie, the film still made Venom his physically imposing self.
So if they ever do have Eddie Brock go up against Spider-Man, as has been implied could potentially happen at some point, the fight will look the way it was designed to look in the comics.
You’ve got to start somewhere, and for Todd MacFarlane, all he really wanted to see was that the big screen Venom was a big ass dude, and as far as that part went, the movie came through.
Venom End Credits Scene | What Happens, and What It Means