They were trendy in the 70's. Decoration only lol. Still available from places like Ceeway ready cut but can come attached to the crown as cast. My Falcon has them but round holes only.
https://www.framebuilding.com/NEWPARTSPAGES/Cast Fork Crowns.htm
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They may look decorative but are far from. They actually serve a very important purpose. Those long fingers serve to "feather" the transition between thin fork blade and rigid crown. Had they not been there, the joint creates a stress riser and eventually the fork cracks there.
Anything with long fingers, even if they are not part of the crown like in your photo, is good. Anything like this:
is positively stupid. This is a Cinelli invention IIRC and the sharp transition caused forks to crack at the bottom of this lug. Cinelli marketed this as a "unicrown" or something - I can't remember now, but they are deadly. I had a Pinarello with such a fork and that cracked exactly along the bottom circumference of each fork blade insert i.e. at the bottom of the lug as seen in the picture above.
The way to think of it is to think of a fishing rod - standard tapering rod. Now think of a stepped rod. Where will it break? The analogy is not pure though, because forks will crack in fatigue whereas the rod will break in flexion.
