"Additional seating" refers to extra chairs, sofas, or any furniture used to accommodate more people in a space where seating is needed. Full definition
Luxury amenities include a dining table for eight, a private powder room and a large bar featuring five bar stools as well as additional seating for at least 10 guests. (redrock.sclv.com)
Use it as a space saving bench in either the hallway or boot room or as additional seating in the living area. (chalet-shop.com)