Well, advantages are mostly that it's interchangeable (fast) and modular. Take your PC with labview or sth. else and keep it running.
For that reason, it is nice if you need a lot of data (logging), want to process the data (for example the temperature drift of a component under test) or for batch testing where you test a lot of components and build a rig to just plug them in...or just fast measurements.
....so you see, it's not just the USB device, it's also the Software. They are pretty accurate, but not as accurate as a really good Benchtop Multimeter. The PC has less influence, but depending on your needs you may have problems with USB data rates or so. Not a concern for private users I guess.
We use some of these (Redlab....much cheaper and OK, Multichannel) to log data on our Ground Truth and Profiling Station. We opted for a USB device because we can readout the Sensor with a voltage output, calculate the data and statistics from that reading and store it on a PC as backup and send the data to our Server for further processing.
For normal use and experiments, it is nicer to use a Benchtop. Often they offer a USB or GPIB option so that you can connect the Benchtop meter to your PC for automated measurements. Then you'll have more or less the same as that USB device but not that fast.
There are also stand alone System which are modular like a USB setup, but don't need a PC. Have a look for that VXI, PXI, LXI Stuff..... pretty interesting stuff, but expensive and too much for normal needs