Thank you both! I appreciate the info and advice very much!
I'm continually disgruntled at how misleading pattern envelopes can be... it says on the back that pleats create the cowl neckline, yet lo and behold, get to step 8 in the instructions and you need these weights! I've found that the 'beginner' rating on vintage patterns is also a bit subjective... I wouldn't consider anything that involves weighting a neckline to be 'beginner' territory.
Anyway, thanks so much for filling that gap in my sewing knowledge! Hopefully I'll go on with the blouse!