Many guitarists feel that multi effects sounds... digital. In a way the multi effect kill their tone, although multi effects are usually much cheaper than a pedalboard full of pedals.
Multi effects are good for starting out, as beginners can experiment and try out the many different kind of effects, to see what effects the person like and what the person dislike.
Fat sounding distortion? lol... FAT. Try Electro Harmonix Big Muff, or Digitech Valve Distortion