The GBA (before the SP version) didn't have a backlight and so compared to the CTRs you played SNES games on were quite a bit darker. That's why most of these games got a brightness bump for the GBA.
I remember that discourse but not really having a problem at the time. I was generally able to see the screen. But I did recently go back to playing an original GBA after years of backlit screens and it was close to unplayable.
If you had Castlevania: Circle of the Moon (one of the launch games), it was an incredibly common complaint. When the GBA SP came out some years later and I went back to "test" what CotM looked like with a backlight, it almost looked like a different game.
I had that game, and seriously gave up on it due to the light. Then one summer at MIT they were offering some nerdy classes for high school kids and my parents let me take a couple. For whatever reason I ended up having to wait around for a long time, so I brought my GBA.
It was then I found this area with amazing natural light coming from the ceiling. And I realized I could finally play castlevania! It ended up being one of my favorite games.
That was one of the games I played. I did have a Worm Light for playing in the car but don't recall otherwise using it.
Of course, I later modded my GBA twice to make it more satisfying to play. The first added a TV out. The second was the Afterburner front light which I did not do a very good job with.
I think it depended on the game. Games designed with very high contrast art worked well, but games that didn't make that choice upfront were painful. My favorite game on the device was Mario Kart, which was pretty hard to see.
You can buy a new shell and an IPS screen with adjustable brightness for $45 on ebay. I'm excited to revive my old GBA that has a terrible looking silver finish and scratched screen.
This comic accurately describes the experience:
https://www.penny-arcade.com/comic/2001/06/13/lame-boy-advan...