It is most desirable to have some contrast to the main color present in any decorating scheme. Rugs can frequently supply that desired contrast. especially since it can be added in small doses and therefore blend into the overall decorating motif without affecting the overall design.
For instance. if a room has walls that are copper or a related color. bringing in reds that are related in tone to the copper tones of the walls will work best. Like a musical piece, the higher notes (light colors of the walls) contrast with the lower notes (the darker colors of the flooring). Using the same metaphor. you would still need higher notes in the form of brighter colors and harmonizing notes in the form of blending colors in order to keep some interest in the overall design. https://tommynevins.com/vinyl/place/kitchen/