I am not sure what you are referring to by "skinny." The gauge of metal used for that deck is the same, or even thicker, than comparable decks so it certainly will not be any weaker and, as with any 46" rated deck the cutting width will be a full 46" so no additional cutting passes or abnormal speed limits should be required.
If the deck appears shorter front-to-rear to you, then it could be that you compared it to others that were not a three-blade design like this deck. Two-blade designs stagger two blades to cover the width and still provide some overlap so that no strips of uncut grass will occur between the blades. This model uses three blades, which means the blades can be relatively smaller than two blades would be to cover the required width. Since three relatively smaller blades, more or less in line, take up less length than two comparably bigger blades would, the overall length of the deck from front-to-back can be less.
Both designs have positives and negatives, but typically the larger the deck width becomes, the more consistent coverage becomes with three blades since the relatively smaller blades allow more positioning options in the available room under the tractor for optimal overlap of each others cutting areas. To cover a large width, like 46", with only two blades would require quite long blades and that length means they become hard to position so they will cut 46" of width and still overlap each other effectively.
Any other differences in appearance are mostly down to slight variations in belt routing or other basic design considerations. For example, this deck uses two belts to run the blades which can mean more maintenance checks, but it also means the belts can be routed more simply than on a comparable single belt system so more reasonably priced belts can be used without compromising reliability and the system may also appear smaller overall.
If I have misunderstood your question or you would like more detail, feel free to submit another question with a few more specifics on what you are looking for. Or you could check Sears.Com for additional information or may want to visit your Sears Store and discuss the details in-person with a representative there.