I like the Apple Smart Folio and I'm using it on my current 12,9 Pro (3rd gen) but it's not protecting the sides and in fact, I've damaged my iPad in these spots, which has never happened on the iPads I've owned before.
I'm not sure why Apple designed this case that way. Maybe it's a design matter, maybe it's because of the speakers. Surely the sound must be not as good on cases that cover them. But Apple could still have protected the right side of the iPad with the Smart Folio, which they left free as well with no reason if you ask me. So I'm not sure if I'll get the Smart Folio again.
I'm not sure why Apple designed this case that way. Maybe it's a design matter, maybe it's because of the speakers. Surely the sound must be not as good on cases that cover them. But Apple could still have protected the right side of the iPad with the Smart Folio, which they left free as well with no reason if you ask me. So I'm not sure if I'll get the Smart Folio again.