What is purpose of fullers on blades?

[fernando]

Sorry to come up with a recurrent source:

https://en.wikipedia.org/wiki/Fuller_(weapon)

This because in my home language we mainly (only) use the term 'goteira' (from the Latin gutta =drop ) as for blood dripping, although we (some) are aware this is a fantasy.
It would however be interesting to know how such connotation was born ... semantic wise.