They are more than just aesthetic. Not all 25x pens will have the cracks, mine don't, but you pay more for such pens when you buy from someone knowledgeable enough to know if the cracks are there.
Take a look at a typical nib of the period. Here is a 144.
and a 264 below a 146.
Note the length of the tines compared to the width at the shoulder.
Now look at the tine to shoulder ratio on the wing nibs.
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