Numbers work as names, and they're easier to generate. If your brand is strong enough, the numbers indicate exactly what they are: variations on a theme. If you only have a couple products, go ahead and name them all, but numbers really work better when you're doing a ton of iteration and minor differentiation in what you produce.
I like it when products compete on specifications, then a number can be important, and a brand. I'm reminded of chevrolet whenever I see a pound of butter because they own the number 454.
The number for my cell phone is just a serial number for the accounting and parts department people. It has no other useful information.
This is an interesting article. I'm always miffed by numbers as models for cars and computers. In some cases, like BMW, it provides an air of sophistication. But it's lost on me. Once again, it all comes down to branding. Sometimes, branding isn't meant to impress but maintain brand consistency.
Someone please tell this to the Java (JSR xyz, nnn, yyy, etc.... ) folks.