MTB shoes have stiffer soles than an everyday shoe and this means that they transfer more power to the pedals each time you push down. By improving this connection between your foot and the pedal you can ride longer thanks to this increase in efficiency. The sole is also textured giving you grip when dismounting or walking on offroad terrain and unlike other forms of cycling shoes MTB shoes are more of an ‘allrounder’.
All the biggest cycling shoe brands release a collection of mountain bike shoes which means that you’ll never be short of choice.