I have a place in my heart for hardwood, especially walnut. But there are so many materials used in furniture, Id like to cover as many as possible over the course of this journal. Plywood, MDF, Particle Board, and OSB are all sheet goods that are often substituted or used along with hardwood in furniture. They can have their place, but are often used as cheap substitutes and to reduce manufacturing time and cost, but this is not always the case.
OSB stands for Oriented Strand Board.
Really not used often in building furniture, but below is a great example that prompted me to start with this overlooked material. Jory Brigham, out of California used it superbly, laminated together to make the Chumash .
The texture will definitely show through when painted. Its also held together with glues and possibly formaldehyde, though this is becoming less common. Its most often used in construction and as an easy, textured substitute for drywall in shops.