Yes, it is. Especially for a hard surface model like a couch. You could easily drop the polycount down to about 2 à 3 K (tris), and still obtain smooth edges.
You could for instance first create the low poly mesh, define the outer shape and chamfer or bevel the edges you want to look smooth, then make a high poly out of the low poly (subdivision), and sculpt in more details (wrinkles, creases, etc...), and finally bake the high poly mesh onto the low poly, which will then create your normal maps that will make your low poly mesh look high poly .
For a character model that is seen close up (main character for example), 12K (tris) isn't too much these days. But, if you can go lower, so much the better.