The whole point of an adjustable wrench is that it makes it irrelevant whether you're working on SAE or metric nuts....the wrench simply opens and closes to match the size needed.
To sell a set as metric and a set as SAE is just money grubbing and preying upon people's ignorance.
And if you're not sure of the size of the nut you're working on and using an adjustable wrench, does the scale really do anything for you? You don't know the size........
And if you say, "Well, once it fits, then you can look at the scale and then pick out the proper size socket....", that's just stupid. Anyone who works at all with nuts and sockets begins to be able to determine, within a size or two, what socket size you need. Try it, if it doesn't fit, move to the next size, up or down, necessary. Repeat as needed. Takes all of a few seconds.