You don't see it because cooktops have electric and gas connections that aren't attractive and that would be exposed. Also, they have safety requirements for landing spaces on either side and behind them. You need 15" on all non working sides. And that's just if you want a separate cooking station. If you want to also prep beside the cooktop, you need to add in another 36" of prep space. If this work table is to be an island, then you'll need 42" aisles on the sides between the cabinets and the table. You're up to a pretty darn big kitchen by the time all of these requirements are taken into consideration.