Hi, Fernando,
It is just as you wrote: the form of the blade does serve a lethal purpose. I even see it in the same line of formal development as the Late Gothic
langue de boeuf and the early Renaissance short
cinquedea.
What makes me wonder if that lethal purpose could still be reached with your partizan/spontoon is the relative thinness of the blade and of its central reinforcement ridge. These two were, in my opinion, somewhat more accentuated in former blades meant for actual fighting.
Again, this is not the field that I can plow with sufficient authority though.
Michael