What you are talking about should be something like OVATION. In fact, the back panel is not made of wood. OVATION's patented material. As for domestic imitation pianos, I think they are just a fucking piece of plastic. OVATION is a grape sound hole, which is also patented. It is said that the sound is more balanced.
These pianos are a minority, not the mainstream. If it is OVATION, you can consider buying it. It's no good if it's not plugged in, but it performs pretty well after it's plugged in. If it's an imitation piano, forget it. It doesn't mean anything, it's just cool in appearance.