At least they got OLED style touch screens, and for a while it looked like everything would go that way but at least in cars some are going back to physical buttons.
People do that in real life all the time even with the ability to do everything on one handheld device today. People pick up preferences for using "apps" on specific devices, or have multi-tasking use cases where flowing across devices feels nice or makes the most sense.
For instance: Using an iPad to read a kitchen recipe and calling to Alexa or Siri on a nearby Echo or HomePod to set a kitchen timer while watching a show on a kitchen screen, say powered by an Apple TV. The iPad could picture-in-picture the show and track the timer and show the recipe all at the same time, but that's not the experience everyone wants. It's not even the experience that Apple wants to sell to people. If you've got an iPad and HomePod in the same room and call for Siri, the software is built to prefer the HomePod and its smarter array of microphones to listen for what comes next. It's better, more dedicated hardware to help the software deliver a better experience.
It's great that one device can do everything, but we rarely want to use one device to do everything when we don't have to. Especially because human memory is contextual and spatial it becomes easier to remember where we "left" things if they are on different devices in different places.
Especially in TNG it feels like a lot of the screens are designed for exactly that: the screens can change to other displays but most often don't because they are very specifically tailored to each specific place they are. That seems somewhat intentionally designed to help the human memory and better muscle memory, knowing what we knew in the 90s and knowing what we know today. "I don't want to lose my place in this recipe just to set a timer or to catch up on TV" is a human problem and TNG showing "I don't want to lose my place on this PADD so I'll ask the computer to do something or walk to engineering to touch a specific dedicated panel that my fingers have already memorized" is maybe just a reflection that in Star Trek's future humans are still, you know, human.