And what you usually run into with the high capacity scales is the incremental increase is greater. That part is not mentioned in the ad.
What I mean by that is a 500 gram scale might read in .1 gram increments, and a 5000 gram scale might read in 1.0 gram increments. That scale may well read in 10 gram increments. To get a high capacity scale that measures in small increments greatly increases the price.
It also has an accuracy factor of +/- 10 grams.
While it would work for full adult balls, it's not really suitable for an entire collection. Like Scott said, it's just overkill.
I use a scale made by My Weigh. They no longer make the exact model I use but this one is similar:
http://tinyurl.com/3x64kn
Mine is a 6000 gram scale that measures in 1.0 gram increments. I also have a 250 gram in .01 gram increments, but I rarely use that one. The one I linked to is a 7000 gram scale and I believe is the model that replaced mine.
You'll rarely have a female ball go much over 3000 grams. There are exceptions of course. However, it's unlikely that "Likity" will ever see 6 feet in length let alone 8.