My opinion is that these spikes are due to the smithing.  
Since you need to improve the weight on that end, you have to amass metal there; creating those spikes is a method to both amass the metal, and also provide the weapon with piercing points.
Even if this is to be tested, I believe that these spikes would be useful in piercing a mail armor, as well as to catch an opponent's vest and unbalance him.
By the way, there are many shapes for flachions: my one, as Masi said, looks like a cleaver, and its design is one of the earliest.
In this very interesting site: http://www.medievaltymes.com/courtyard/maciejowski_images_32.htm you can scroll through the Maciejowski Bible's miniatures.  
It's a book from 1240's, and shows plenty of Medieval weapon, clothes, tools and such.
Judging by how soldiers use their weapons, it seems that almost any kind of sword was used for slashing, as well as axes, while rare maces are used for blows, and piercing was done using spears!
A very great resource, indeed - there's also David slinging at Goliath  
 

 
Greetings,
Mauro.
 

Short swords like the wakizashi can be less than 2/3 of a meter total and some swords traditionally have full tangs with handle slabs, the szabla of Poland being one. They were designed to have replaceable slabs: rough, carved wood for fighting and jewel encrusted ivory for dress. The Messer was a single edge long sword, the blade on a Messer is the same length as an entire falchion, albeit narrower so that it isn't so heavy that it's unweildly.

Techniques for langes messer (essentially a falchion) from Talhoffer. The hand being chopped off is an image that stays in the mind!
 
http://youtu.be/bWISsk0cy74
 
 
And I stand corrected. A messer was probably a common mans weapon whereas a falchion, also a falchion is indeed a sword, a simple google picture search shows the pommel and peened tang the messer lacks. I was conflating the two. I was going more on the blade shape and length I guess. Truly a terrifying weapon! Here's a YT clip of test cutting with one. The cutting technique is ok, some stepping before the blade arrives but way (!) better than the overpowered cuts shown on the Cold Steel vids.
 
 
http://youtu.be/noyKVT5dSYU

Yes, these weapons were impressive!
Imagine to fight with a longer machete  
Greetings,
Mauro.