White watercolor pencils- are they worth using?

My watercolor pencil students know that I recommend General's Kimberly brand as a good artist grade watercolor pencil. The basic 12 pencil set has been a staple of my workshops for quite some time now. The colors in the set lend themselves to the Sedona landscape quite nicely. I purchase sets in bulk, and my latest shipment came with a substitution of the "straw" color with white. I have always derided white as being a worthless pencil, especially in a small set.
Now, I am usually not one to complain, but I figured that if no one spoke up, the company would never know. I searched them out on line, and sent them an email explaining my opinion, and position regarding white pencils.
I received a response very quickly, urging me to call a specific person at the company. I called, and talked for some time with the very friendly customer service rep, and fully explained my concerns and needs.
In just 2 short days I received a package with replacement straw pencils along with a few extra items.
I really appreciate this fast and friendly response to my inquiry. I will continue to use, and recommend General's Kimberly pencils to my students and colleagues. I find them very comparable to brands costing twice as much.            
My question to you is, have you found any use for white watercolor pencils? They are not opaque. If you need to tint something, just add some water to dilute the color.
Maybe I'm missing something here.

A couple of recent pieces, using General's Kimberly Watercolor Pencils. Enjoy!