Some judokas like to make that difference between the two throws, they see Hiza guruma as a wheeling technique where you have to pull your opponent into a wheel or semicircle, while Sasae tsurikomi ashi is a linear throw where you just have to sweep your opponent’s foot without having to move your opponent in a semicircle.
Personally, I don’t agree with this distinction, I believe that both throws can use that wheeling motion trick (as explained in step number 5). If you watch high-level judo matches you will notice veteran judokas apply the same trick on both throws