I wish they made it easier to find games that support simultaneous mouse and game pad inputs, since I like to map mouse to gyro and ideally get analog joystick movement over having to map movement to WASD. And better if they put down whether the game supports locked glyphs so it isn't switching between keyboard and gamepad icons due to detecting mouse and gamepad commands.
Yes, that is correct, but sometimes games implement controller specific features that you might want to use. For example: the haptic triggers on the Dualsense.
Steam's new update simply allows you to see which games support the extra features of your controller. You can still use whatever controller with whatever game.