Adjustable "Metric" and "SAE" wrenches?

[havasu]

I came across this ad from Costco this morning. I consider myself fairly knowledgeable, but I just don't see why there would be a difference between these adjustable wrenches, except for the length. Do we really need an American and a metric wrench? What am I missing?

Here is the ad:

The Irwin 7-piece SAE / Metric Quick-adjusting Wrench Set is a great set of wrenches to have on hand that will cover a variety of sizes

This Quick-adjusting Wrench Set uses parallel jaws with smooth surfaces to help protect the surface being worked on. The wrenches in this Irwin set use precise scale markings to get an idea of what size bolt you are on and the whole system runs on a grooved internal jaw and sliding lever. Each wrench has the ProTouch grip to help provide the user with maximum comfort and reduced hand fatigue.

Features:

Parallel jaws with smooth surfaces
Precise scale markings
Grooved internal jaw
Sliding lever
ProTouch™ grips provide maximum comfort and reduced hand fatigue
Hang hole for easy wall storage
Lifetime guarantee
Wrenches Included:

6-inch SAE
8-inch SAE
10-inch SAE
12-inch SAE
6-inch Metric
10-inch Metric
12-inch Metric

[phishfood]

Looks like a way to sell you the same set of wrenches twice, at the same time.

[havasu]

Seven different wrenches!

[tr888]

I suppose the tick-marks are in 16ths or 8ths for the SAE and in mm for the metric.