<p>I am learning to use LabVIEW as part of my honours project, and was wondering what benefits the graphical programming language has over a textual one?</p>

I've used labview before for calculating parameters to tune an nMRI machine.  They exist because in theory it is easier for someone with little programming language experience create a program.  The control flow and decision structures can be arranged graphically and they can type in their formula's where they want.
For professors and lab assistants...helpful.
For real software developers...it would be easier to write in another language.