best for spark transfer; dull or sharp edges?

If they propogate easier off an edge the (ND) U-groove marketing may be right? Here is an opinion:
"..Sharp points ionize the surrounding air more quickly and it will conduct sooner and more reliably, with a more concentrated spark
that is supposedly hotter. It's why platinum plug electrodes are so
thin. And it's why lightning rods are pointed.
The (NGK) V-groove (and ND U-groove) leaves more sharp edges to do the job than a
square-cut elecrode."