That is a fair point. Just looked at their site, it's common for them to offer 2 grits per set of stones. So if you look at their 100/200 grit pair for $70, it would be the equivalent of getting 2 Edge Pro diamond stones. As a point of comparison, I looked at the Edge Pro Atoma stones at CKTG, they are roughly $50 per stone, so $100 for 2 grits. Some of the other branded E.P. diamond stones cost even more per stone.
The point being, the cost of the W.E. sharpening media, considered in isolation, don't seem out of line compared to other guided systems. I think the OTHER aspects of W.E. can be pricey, but the media aren't bad at all, when you compare to guided system stones.
However, sorry just have to say it
: if we're going the route of comparing the cost of sharpening stones as an input to the OP's decision, freehand sharpening and bench stones is gonna win that contest hands down. If you come up with some kind of a metric, like "dollars per square inch of sharpening surface area", there's no way that these tiny sharpening stones of the guided systems--which are expensive because they have to be cut to small sizes, and mounted--are going to match up to the cost effectiveness per square inch of a bench stone. Take an easy example, the mammoth DMT duosharp 10"x4" dual-sided interrupted bench stone. That's 40 sq-in. per grit, and the stone is 2 grits, EC and C, for $106 I see it on big river. That equates to 2 grits, 80 sq-in of sharpening area, and a cost of roughly $1.33 per sq-in. If you go with the continuous (vs the interrupted) DMT, the 2-side EC/C Diasharp is 8"x3", so 48" total surface area, best price I see is $88. $88 / 48 sq-in = roughly $1.83 per sq-in. Do the same math on those W.E. stones: from what I can tell from online info, the surface area of one stone on their handles is roughly 5.25" x 0.75", give or take a small fraction. So, surface area of one stone is 3.93" x 4 stones = 15.75" total surface area for 4 stones covering 2 grits. $70/15.75 = $4.44 per sq-in. That ranges from 2.4x to 3.3x per sq-in more expensive than the equivalent grit DMT bench stones.
Not that cost-per-square-inch of sharpening media should be the main or only driver of the OP's decision. But if cost is a factor, just sayin', it's very hard to beat the cost effectiveness of a bench stone.