Whats the deal: Bearings

[J57ltr]

Why do all the manufactures even put in their descriptions that they use ABEC 1 bearings? These are the lowest rating on the ABEC scale. At the RPM's that motors run (30K-60K) I would think you would want the most precise bearing you can get, or at least a 5 or 7. Believe me I know that the cost goes up I spent $20 replacing the bearings on my Feigao, but why is it that manufactures put it in there like its added value or something?

Jeff