Quentin Beck, a.k.a. Mysterio, is a villain fans have been clamoring to see in a "Spider-Man" movie for years not just because of his fishbowl helmet, but mainly down to the fact that he is a visually stunning and different kind of villain. Spider-Man has one, if not the greatest rogues gallery of villains in comic book history, with most of his villains tending to range from low lives given powers, from freak lab accidents, to men in powered suits who just want to rob banks.
What made Mysterio so great when he was first introduced in the comics back in 1963 was how the character was set up to be this larger-than-life superhero with world-bending powers that even Spider-Man could not get a bead on, only for it to be revealed towards the end that, true to Mysterio's character, it was all a smokescreen.
Mysterio wasn't the next big Marvel hero introduced in a "Spider-Man" comic before spinning off in his book. Beck was an attention-seeking actor from Beverly Hills who used special effects and gadgets to make himself come off as a hero with powers. This "master of illusion" had fooled not just Spider-Man and the people of New York, but the readers themselves.
"Spider-Man Homecoming" introduced Michael Keaton (Batman, Beetlejuice) as Adrian Toomes a.k.a. the Vulture, and he was one of the most well-received aspects of that movie. Not only was Vulture portrayed by a great actor, but Toomes was a fairly drastic departure from previous Spidey movie villains, with no superpowers and no immediate beef with Spider-Man.
It introduced the concept that there are just regular people out in the world inspired by the plethora of superheroes around them and deciding to profit off their existence. The sequel, "Spider-Man Far From Home", looks to continue that trend with Jake Gyllenhaal (Nightcrawler, Donnie Darko), set to play Mysterio along with a great skill set. It has not been confirmed if the film version of Mysterio will have powers, but with how close Marvel has stuck to source material up to this point, it is likely that Gyllenhaal's version will be just as deceptive and misleading as the comic version.
Jake Gyllenhaal is one of the greatest and well-respected actors working in Hollywood today, but not an actor usually seen starring in big-budget superhero or action movies. While the Marvel paycheck likely was a factor, the character of Mysterio is someone perfectly suited for Gyllenhaal and the roles he takes.
Gyllenhaal can play the action hero as seen in "End of Watch", but he is also not afraid to leave his comfort zone and go for the darker, more psychological roles like that of Lou Bloom in 2014's "Nightcrawler." Mysterio should be treated as a character that can put on a friendly face for the public, but he is a conniving narcissist behind the scenes, and Gyllenhaal has proven countless times before that he has the ability to pull that off.
If there was one major complaint with "Spider-Man Homecoming" among fans, it was that there was not enough focus on action and spectacle like the Sam Raimi or even Marc Webb "Spider-Man" movies showcased. Mysterio has the potential to bring all of the spectacle and then some, as he is an entertainer that wants to put on a good show.
Not having any powers is not a hindrance for Quentin Beck as he makes due with his life like illusions that can be a challenge for anyone to overcome, powers or not. Almost anything a writer wants to do with "Spider-Man" can be done through Beck's illusions, and it would make sense.
Spider-Man in a prehistoric period fighting dinosaurs, Spider-Man fighting the Avengers, or what looks to be "Far From Home's" case, at least from the looks of the trailer, giant elemental monsters. Spidey would eventually get to know Mysterio's illusions like the back of his hand, but for a teenage inexperienced Peter Parker, Quentin Beck is a very serious threat.
Mysterio is a villain who will bring a new dimension to "Spider-Man" on film, being a mental threat as opposed to a physical opponent, which is something audiences have never really seen done in these movies before.