Laptops? Sorry, I own a real computer. And i've never seen one on a deskstop, ever. The point is, they are not a Disc replacement. They are for cameras.
Since when is a laptop not a real computer? Mine runs all the same software as my desktop

As for the SD card slot, I'm sure I've seen desktops with built in card readers (can't remember where, I think I've seen Medion and HP machines with them.) And SD cards work fine as disk replacements too - I used to have a netbook that booted AmigaSys from one, and I've used them in place of USB thumb drives if I didn't have one to hand.