I've managed to buy several cameras and lenses during my lifetime
without having the foggiest ideas what I was gettting.
This has changed recently, as anybody who follows my uphill struggle
towards comperhension and extended photographic vocabulary.
Apparently the number of blades is way down the
list of prioritised questions one should ask when choosing a lens,
but when it comes to making "good" rather than "bad" Bokeh,
it can become a consideration.