When purchasing a sofa you have so many things to consider regarding fabric, color, style etc. When it comes to considering if you will purchase a sofa with or without legs you want to consider your space.
Legs on a sofa allow your eye to continue and allows for the space to feel more open and free.
Open space under any piece of furniture will enable a “floating” feel and dynamic in your space.
A sofa which goes all the way down to the ground [almost like a block} is great to use in order to help define an open space plan such as a loft.
You can also use this style sofa to define specific areas within your home/space.