It's called Convertible Sofa because the sofa is transformable or adjustable.
The designer thinks that - when the living space is relatively small - the interior item should be small in size too and adjustable or convertible at the same time so that it can be multi-functional.
Convertible Sofa has these features for it can change from a living room sofa to become a dining table and six seating.
When the dining time is coming, just turn the seat into padded stools for six persons, and turn the backrest into a countertop with extended wings.
The ergonomics side of this small sofa is guaranteed by its maximum comfort and convenience.