Most small LCDs have a controller chip that manages the framebuffer and have a high-level interface like you describe. However, using these interfaces is still

Most small LCDs have a controller chip that manages the framebuffer and have a high-level interface like you describe. However, using these interfaces is still very slow. Much slower than this VGA interface. The Pi Pico has 2 cores so while one core is used entirely to maintain the display the other core can do other things.