Missile units?

I started a new campaign as Venice, bought Bologna on the first turn following advice from some guides here on the forum and in doing so obtained some units of crossbowmen.

When I rightclick them to get their description it states in their special abilities section (in german so not the exact words) that they are "long-range missileunits". And in their long text that they lack the range of bowmen. And in the description of venices starting bowmen they have no "long-range missileunit" ability.

So - what does that ability mean if crossbowmen have actually shorter range than bowmen?