I would say that a higher frequency of changes would keep water parameters more stable.
During a long space between changes nitrates will build up and Ph will drop. Every time you did a big water change the nitrates would go down and Ph will go back up dramatically. Dramatic changes in water chemistry are generally considered bad for fish.
If you do changes more often there is less time for waste products to build up, keeping parameters more stable.
Or to look at it another way, if you had a rabbit or a bird, do you think it would be happy if you cleaned the cage only once a month, even if you cleaned it really really well each month?
Just my $0.02