I've been using internal drives for data backups for years now using a cradle. I wouldn't necessarily call it better, just more efficient for those of us who juggle a lot of harddrives. And no they don't have an accelerometer but I'll guarantee you, if you drop a harddrive from desk height onto a stone floor, no parking of read/write heads will keep it operational unless it is an SSD.
Buy a cradle, set it on floor, so it can't fall. Backup your stuff, label it, put it in a safe. Can't get more secure than that.
And yes I do this with important documents. Using a dock similar to this
http://www.newegg.com/Product/Product.aspx?Item=N82E168... via eSata, when I bought the first one there wasn't even a usb3 standard yet (just careful some are hit and miss). I've used WD black/green, hitachi,seagate, raptors, 2.5 ssd, 2.5 hybrid drives and probably more than these and not once has one of these drives failed using the cradle ever. Note however I've purposely avoided >2tb drives. I still have mission critical windows XP machines that just don't play nicely with >2tb drives. So 2TB drives yay, 3tb drives nay.
Recently I've switched to regular "premade" external seagate 3.0 drives. Got a bulk deal on a 20 pack of 3tb drives that I just couldn't resist. I use a lot of storage and have gradually shifted away from XP, keeping files and program backups that only run on XP still on my <2tb drives.
So to answer the question does it matter? Not really. Just use whatever works for you or is cheaper. Again please please when copying, place it on the floor, not on the ledge of a table. Since recovery of files is very expensive.