Studio probably doesn't care as much about quality as much as cashing in on popularity. Flash is as big now as the character has ever been as far as mainstream recognition goes. On tv, comics doing well, logo everywhere. WB have seen footage of Ezra from Justice League, they know what they've got. It's not an accident the first teaser for Justice League was based around Batman and Flash meeting.
I understand all of that, but I also think that if WB had any real intention on capitalizing on The Flash's hotness right now, they'd have cast Grant Gustin as Barry in the movies as well, since he clearly has brought in a whole slew of Flash fans. I've been a fan of the Flash since the 80's, when my older sister bought me a Flash action figure when I was 5, so I'm absolutely loving all of this new heat the character is getting, but it just seems weird to try and undercut the hit show by casting a new actor. Again, I think Ezra is going to be great, but I kind of wish he was another one of the Flashes, like Wally, Jay, or even Bart Allen. Nothing that Warner and DC have done have made me think they really have faith in this endeavor, just that they know shared cinematic universes are hot right now, and despite having some fun DC shows that are having a great time with interconnected worlds, they want to slap some billion dollars revenues on the film side of things. Understandable as a business, but they've been sloppy handling it so far.
I just want Barry or Wally, or whichever Flash they want to use to get a good movie, when it's time for him to get a good movie. WB and DC have yet to prove to me that they can make a good movie with their tentpole characters, let alone a good movie with a character not as broadly known as The Flash (although to be honest, the fanboy in me can't imagine how anyone doesn't know who The Flash is, but the truth is, a lot of folks don't know who The Flash is, but the show really changed that for the better). I feel like the show is really stealing the thunder from a Flash movie trilogy, just because so many awesome storylines and characters have already graced the show.
A Flashpoint movie trilogy could be really cool, but I'd kind of use that as a end of Justice League trilogy style story to relaunch a new DC cinematic universe when the time comes.