I said the same thing when watching it. Lite Brite is creative but there wouldn't have been any screens with a bunch of individual LED's (and would LED's even light up? What is making the incandescent bulbs light up? And if it can make incandescent bulbs light up, why isn't it causing ALL KINDS of electrical havoc?)
Same reason the one kid was killed by Vecna in the middle of a road, which presumably opened a gate like the other locations of deaths as Vecna himself says that's the purpose of the deaths.... but it was never mentioned or shown again until they needed it to rip open. Convenience.
Would have been a hilarious scene with the stoner van accidentally driving into it and saving the day. Then Dustin angrily and hilariously points out they were climbing a rope like it was gym class when there was literally a gate in the middle of the road right outside the trailer park the could have walked through.
These shows don't get better under scrutiny, and in fact often get objectively worse. Reminds me of the Walking Dead episode where they all almost died because zombies were wearing riot gear at the prison, but nobody thought to keep and wear that gear themselves (until once later as extra ironic plot armor).
As entertaining and great many of these modern shows seem in the moment, few will stand the test of time as classics or literature. Which is fine, and how things work, where people in their own time overestimate the importance and impact of the things they consume (or that consume them).
That reminds me of one of the more interesting exchanges in the book Ishmael where the student is asked to recount his modern, current culture's mythology. He is incredulous, saying it's an absurd question, we don't have mythology because mythology is for long gone civilizations that believed in fanciful things in place of truth, to explain things they couldn't possibly understand. Which is the exact thing a normie Roman would have said in their own time. And the point.
But, yeah, still a fun show aside from some really inexplicable shit and objectively way too many characters and side stories.