In sharpening a grizzly though, you're not sharpening any more metal than you would with a double bevel... it's just all on one side.
To sharpen a single bevel knife you lay the whole, wide primary bevel on the stone, then flip it over and lay the entire flat back on the stone. You're still honing the two sides of the knife, just like a western-style knife, but you've increased the amount of steel that needs to make contact with the stone dramatically.
Think of it this way, what takes longer - getting a mirror polished edge on your knives, or mirror polishing the flats? That's essentially what you're doing with a single bevel knife. With the wide surfaces it's easy to hone correctly, it just takes more time to hone due to the amount of steel.
When I'm marking wood against a straight edge (or using a marking guage) I'm using a single bevel marking knife - it pulls itself into the straight edge and helps ensure the blade doesn't wander out away. When I'm marking free hand curves or anything else, I use a double bevel marking knife - I don't want that blade to wander in any direction and the single bevels pull slightly (which is exactly why the best sushi knives are single bevel).
I have a number of japanese knives in the kitchen right now; I like the traditional construction and love the knives. Only the slicing knife is single bevel. It excells at what it's designed for. I love my japanese chisels as well, but again, with a wide primary bevel and no secondary bevel it takes a little longer to hone than the microbevel on my western-style chisels. I never have to touch them to a grinder though