You can sell/lend/trade the physical copy. The eshop one may be a bitch to get back if you replace your system at some point (broken, stolen, upgraded to a successor). Of course this is true of all physical vs download games.
Well yeah, I use a large laptop as a desktop. But that's why I want one of those pockets- they can get tossed in a bag with ease. I actually have an older device I want to get my hands on though since it uses 2.5 SATA and meets the thin netbook size