Munt emulates a real MT-32.

A soundfont is an approximation -- and can't reproduce an MT-32 anyway, since the MT-32 instruments are programmable.

Thanks for the answer:)
This part I understand: "A soundfont is an approximation"
This one not really: " -- and can't reproduce an MT-32 anyway, since the MT-32 instruments are programmable." - AFAIK folks do use FluidSynth in DOSBox (ECE, maybe) to emulate SC-55 or later models. Am I wrong?

They use Fluidsynth as a General Midi device.
But some Dosbox builds (I think ECE for example) use a built in Munt to emulate a Roland MT32 device

SC-55 (and many other General MIDI devices of the era) generates it's basic sound palette by accessing a bank of preset sounds, similar to how Soundfonts function. That is why Soundfont-based systems can be used for emulation.

MT-32 (which is not a General MIDI device) generates it's sound palette PARTLY by the above method, but ALSO by certain unique methods involving custom sounds and real-time calculations. Therefore, soundfonts cannot by themselves suffice to emulate an MT-32. The application "Munt" was written specifically to fill that MT-32 niche, with the necessary real-time capabilities in addition to the stored bank sounds.

Now it is clear.
Thank you.