Both of my slides are higher than the regular floor, but one has the kitchen cabinets and sofa hanging over the edge, so there is no obvious height difference. Personally, I see that the configuration in your photo as being very dangerous because I can guarantee you that I would trip over it at least once per day! On the other hand, I need to replace my couch but it is going to take a couch that has been modified to sit on the higher slide.
My bedroom slide goes under my bed, so there is only a height difference when you enter my bedroom, but luckily I have tripped on it only twice in 9 years.