Hmmm. I just checked the help entry for this. The only examples given insert a file from the website into a container field. Don't know if that's the only option or if their documentation is incomplete.
If you try using this to insert into a text field, does it work?
Bottom line for many questions of this sort is to run some tests and see if it works.
Hmmm, just ran my own test and was able to insert text (filled with HTML tags) from a specified URL into a text field. This suggests that this may work, but you may have to do a bit of "post insert processing" to extract the value from a block of HTML text.