I have two toasters (NewTech Voyager). I got tired of buying externals over and over.
With externals, you're paying for an enclosure every time you buy a drive. And then you have to store it. With the toasters, I can pop in hard drives like floppy disks. Fill em up, stick em on the shelf.
Externals are great if you have to frequently MOVE your drives from one place to another. If you have a home studio or office, they're overkill.