Yes. Very often. I use SYS_EXECUTE to call a vbscript which I have previously written to a file using something like SYS_EXECUTE("CScript something.vbs"). Actually, this is an oversimplification as I actually call a shortcut to a file with this text in it "CScript blah.vbs". This is because of the 'wait for completion" thing. I sometimes need to send characters to the cmd window after I call the CScript (to wrap runas, for instance). Thus, I need to have a branched/asynchronous launch. It sounds convoluted, but I works like a charm hundreds of times per day when my scripts run.
Yes. I then create another file which is a shortcut to the temp.bat so that I can interact with the running vbs script (when necessary)... a bit messy but I use a 'scratchpad' folder to keep all my junk in. If you can simply wait until the script completes to continue with your script, you have all you need already.