No one would argue that solid hardwood isn't a sound building material, but its tendency to warp if it hasn't been properly dried can be a disadvantage. Because it is laminated in perpendicular layers, plywood doesn't have this tendency, so many woodworkers prefer it for constructing wide surfaces, such as tabletops, cabinet sides and tops, and even shelves. The equivalent construction with hardwood boards involves laminating them together, which is a time-consuming extra step that doesn't always eliminate warping. On the other hand, hardwood is the preferred material for legs and structural joinery, for which warpage isn't as much of an issue.
Woodworking enthusiasts appreciate hardwood for its texture, color variations and even aroma, and plywood doesn't share the same qualities. Plywood is primarily a utilitarian product: easy to cut and assemble but difficult to fit into anything other than purely geometric patterns. Hardwood, on the other hand, can be turned, routed, beveled, shaped, bent and combined with other hardwood to create interesting patterns. It is possible to mold and shape plywood, as makers of avant-guarde chairs and furniture have demonstrated, but the net effect is different. Nevertheless, its edge pattern of overlapping laminations can be used to advantage in a modernistic design motif.
When it comes to sanding and finishing, a hardwood surface and one constructed from plywood with an equivalent hardwood veneer take the same amount of effort and look the same when you're done, but there is a significant difference in the edges. Plywood edges reveal the lamination structure and usually must be covered with trim to preserve the appearance of the veneer. The trim usually has to be nailed, and it usually isn't possible to completely hide the nails. Moreover, there is a discrete boundary between the plywood surface and the trim that identifies the surface as plywood.
The comparative expense of using hardwood over plywood for tabletops, cabinets and shelves is often a deciding factor. At the time of publication, a 4-by-8-foot sheet of red oak-veneered 3/4-inch plywood cost about $50, which is about $2 per board-foot, while the price of solid red oak lumber was about twice that. The price differential is typically greater for rarer species. Expense is another reason why woodworkers often use plywood for flat surfaces that consume the most wood, reserving hardwood for design features like trim and handles, and structural necessities like legs and spindles.