I used to play in a Concertina Quartet, The music was arranged for 4 parts, often there were metronome indications for different sections.
as we used to practise the parts seperately at home, using a metronome to get an idea of correct speed was very useful, we all then had a good idea of speed of a particular section when we played together.
often the music had several bars rest for a particular player, being able to count the beats accurately was assisted by using a metronome.
if the player didnt count correctly he messed up the whole arrangement.