Closed-hole (Plateau) keys have a solid, fully covered surface, making them significantly easier for beginners since finger placement doesn't need to be perfectly precise to produce a clean tone. Open-hole (French model) keys have a hole in the center of several keys that the finger must fully cover, which is more demanding to learn but is considered standard for advanced and professional playing, partly for the subtle pitch-bending and tonal effects it allows. Open-hole flutes are commonly sold with plastic plugs to temporarily fill the holes while a student is learning, functioning like closed-hole keys until they're ready to remove them, which is a practical detail worth checking for on a used open-hole flute.