One of my favorite elements of Montessori philosophy is the environment - the purposeful, aesthetic, yet simple space for baby (or child) to be, sleep, and explore. Everything is designed to fit the child's development and size, changing as the child grows. The purpose of the environment is to promote independence, respect, and freedom to move. One traditional (and sometimes controversial!) component of this environment is the floor bed, though it is most definitely not a necessity.
I was pretty excited to try the floor bed, but have always kept in mind that it doesn't work for every family, and it might not always work for ours. D began sleeping in her floor bed around 5 months old, when she transitioned from a bassinet in our bedroom to her own room. We started with just the mattress on the floor, which worked for a while until she began to accidentally scoot or roll off in her sleep, sometimes waking her up. So my husband agreed to build her a floor bed frame, giving her access to scoot out, but enough of an edge to prevent accidentally rolling out. With the beautiful frame, she also loves to scoot to the corner of the bed, creating her own little nook.
They toughest part of having a floor bed is baby-proofing the room. Even though D isn't crawling out of bed at night (for now), the shelves are low, the outlets are child-safe, and there are no heavy or large pieces of furniture or decor that could topple. We do still have a changing table but it is anchored to the wall, and the drawers are simply canvas, with the lowest one holding cloths that are okay for her to play with. As she begins to climb, we will adjust as needed, likely removing the changing table and nursing chair. We also always have the baby monitor to make sure she's safe!
Although D isn't crawling during sleep hours, she does love to crawl around her room during awake hours. I find it so nice to have a room that I feel safe letting her play in without saying "no". Before and after naps, she can scoot around her room, play, and explore. I try to keep the "quiet" toys (books, stuffed animals, puzzles) in her bedroom to make it a more peaceful space, which is important when she is playing in there pre-sleep. I save the music making for our living/play room downstairs
As we wind down before sleep, one of my favorite parts of the floor bed is that I can sit with her on the mattress, tuck her in, and kiss her goodnight. She is (usually) happy to be placed down in bed, and babbles and wiggles to sleep. I think starting the floor bed pre-crawling has also helped her be comfortable with it as her place of sleep. My hope is that as she gets older, she continues to enjoy this bed, as she is given the freedom to move and to sleep when she is ready. Only time will tell!