Lay flat hardcovers are much nicer for taking notes from. You can place on a flat surface and use your hands to do other things. A paperback will typically need a book weight to accomplish the same thing.
I own those, I would describe them as semi-hardcover, with fake leather wrapped around some stiff but still pretty flexible material. The text is also so small as to be difficult to read in all but ideal lighting.
Tbh I have a worn UK first edition of one volume (stored for now, I think it was TT). Beautiful fold out map, but the cover was cheap and flimsy. I think my latter US 2nd edition was better manufactured, not sure if that’s a postwar UK problem or not.
If you have a normal size backpack carrying a normal size load like you are going to work or school, it’s easier to slide in a smaller paperback than a bulkier hardcover. The extra volume makes a difference in this case.