All external drives are moving toward USB integrated interface. So, it makes sense to have and it is a much better environment that any operating system based machine that would try to talk to the drive. However, it is not a savior most times. Typically, drives require much more advanced work, as damaged/weak mechanical components cloning over USB is like pulling hairs without really getting anywhere.
It is a matter for math. Do you get a decent amount of drives coming in? If yes, then the cost should be recovered fairly fast.
And it depends on your system... if you are a computer shop, then perhaps you don't get as many USB external drives vs. drives coming out of machines.
May also consider buying a used version and save few dollars. Search around..
