Also the tread pattern is asymmetrical on the NT01 which makes them great for flipping them left and right. Something you cannot do with the 888. To me that's a plus as I try and even out the tire wear.
The NT01 is asymmetric and non-directional; the R888 is symmetric and directional. Each has its advantages, in performance as well as convenience.
The main advantage of an asymmetric track tire like the NT01, as noted on Nitto's website
here, is that the tread pattern is optimized for track use, where hard cornering puts different needs on the outside part of the tread than the inside. From a convenience standpoint, it can be moved from one side of the car to the other without the need to dismount it; however, this also means that any uneven wear between the outside edge and the inside edge cannot be evened out by flipping it on the rim, at least not without losing that performance advantage. Also, in my personal experience, the profile of the NT01 includes rounded shoulders at the tread edge, such that it can get worn down to the belts on the edge while there is still usable tread depth in the middle of the tread. (By contrast, the RA-1 has squared off corners so the tread can wear out evenly across the width of the tire.)
One advantage of a directional tire like the R888 is that the symmetry puts the added grip along both edges of the tire, as described on Toyo's website
here. A second advantage of a directional tire like the R888 is that such V-shaped tread patterns help shed water when used on wet pavement and particularly in standing water. In terms of convenience, if the car is wearing one edge more than the other, as is typical with the outside edge on the track, the tire can be flipped on the rim to even out the wear between the two edges, although this does mean dismounting and rebalancing, typically done halfway through the tire's lifespan.