Skill: Shows off the blacksmiths massive horse cock. In a time before modern machinery some crazy Germans and Swiss hammered beyond natural human limit. They probably did it as a meme then realised it was actually useful as a weapon. Sharpening a wavy blade would have been a nightmare.
Functional: Good for duelling sword vs sword. A traditional sword allows you to slide off an enemies blade if your swords clash, because the blade is straight. The waves in a flamberg blade creates vibrations which hurts the opponents hands, that doesn’t sound like much but it gives you an advantage. Very useful for parrying since the enemies sword will strike, then the blade gets stuck on your wavy blade or they pull away from the impact shock. Either way you will have an opening to attack. Also the waves cut much deeper similar to a serrated knife. If you got cut once by this blade, you would not be able to stitch your wound shut, you are pretty much sliced bread.
Aesthetic: Someone challenges you to a duel, while they unsheathe their boring longsword, you unwrap your wiggly sword. They immediately apologize and run because you are rich enough to afford a wiggly sword and probably have multiple wenches giving you ankle parchments.
Item:Flamberge; in addition to the old 3.5 stats at the link, while not everyone recognizes the dangers of fighting someone with a wiggleblade, +4 on Intimidation checks against Fighters and others with knowledge of weapons.
Procrastination Station 