People were clamoring for early access to betas and buying seats on developer accounts just to get it. Their public beta program just endorsed it and also allowed them to send actual developer betas to developers ahead of the public betas.
> Apple has been using the public as their QA team for last many releases.
Are you referring to the Apple Beta Software Program? Would you rather them _not_ allow people to test their beta software so more bugs make it into the public release?