I liked the sound of this idea so much I went to the 24hour website and did a map search of their western states locations.
Answer: if you like camping in large metropolitan areas this might be a good solution. I expected to find far more locations in rural exurbia, for example Bend, Oregon--and similar small-to-medium pop centers near to outdoors attractions. To me, free camping doesn't mean much if it's 200 miles from where I want to be.
Another problem is that most locations seem to be in regional shopping malls where the mall policy will determine whether you get hassled for parking overnight. Doesn't matter how much 24 hour would love to have you visiting the facilities at three in the morning. Mall security will be driving the lot and rousting you.