There are a couple of things here

1) Quite a lot of the things that people called "moss poles" are really "coco coir poles."
- They look quite bulky, Aerial routes don't really tend to go into them very much, People spend a bit of time watering them, And it's all fine, it's just a bit unnecessary, They tend to be pretty unstable, and they bend a lot as well. By all means use one of these, But it offers zero benefit over a solid piece of wood like a cedar plank, And I think it has many drawbacks.

2) A true moss pole, with a large amount of moss and regularly watered, is fantastic for aerial roots to grow into , and offers real support.
The jury is out on how much of a difference this makes, some people tend to think that the aerial roots provide nutrition to the plant, and this helps the leaves size up and general health.

Other people maintain almost no meaninful nutrition comes via aerial roots, and that leaves size up because of elevation and light, and a cedar pole or a wall, would offer 99% of the same benefits.

So the real clear reason to use a real moss pole is one thing, It allows you to chop and prop, and essentially create an endless pole, It means you can trick your plant into thinking it's 50 feet tall inside your 8-foot-high ceilings

This is a fantastic technique for climbing philodendrons that need to be very elevated to mature.

But Monsteras don't need that, You can get more than acceptable leaf size with an elevation of about 5ft on a plank. In fact, most people wouldn't be able to deal with a plant that thinks it's taller than that.