Notessimo only uses volume values where as DAWs have both volume and velocity. In Notessimo when you increase the volume of a note it simply increases the amplitude.
Velocity is midi data that ranges from a value of 1 to 127. Velocity affects both amplitude and sample playback. Higher quality sample libraries have different samples based on the velocity of a note (eg. a piano or snare sounding more bright and percussive at high velocities).
Here is a SFZ file that uses velocity ranges to play back different samples
K18-Upright-Piano.sfz (21.1 KB)