Brightcolours, I think you're confusing the needs of professional cinematographers with those of hobbyists who want to video their family and friends. For them, spontaneous scenes with moving subjects such as kids and pets are the norm. This is where the Sony solution provides a much better solution than the CDAF used by other DSLR's - the former provides constantly sharp subjects, while the latter turns out mostly out-of-focus videos with some jerky AF in between.
As to why use DSLR's instead of camcorders, I think we've already discussed this, but I'll be happy to explain the reasoning again.
As to why use DSLR's instead of camcorders, I think we've already discussed this, but I'll be happy to explain the reasoning again.