It is all about manipulation so they can mould a storyline where there probably isnt really one.
To make the action seem faster paced and more exciting than it really is so they can appeal to a younger audience which is an audience that is worth more to advertisers.
They can command bigger fees from advertisers if they can present figures that show that the average BB viewer is say 16-25. A young demographic is an advertisers dream and they will pay a premium to get to it.
Unfortunately it is all short term gain as it is destroying the shows loyal audience and replacing them with casual viewers that will and are going to get bored of it.
Most shows only have a short shelf life BB has been an exception but now C5 have ripped its guts out and gone for the short term gain it wont be long before its dead and buried unless they return to the proven winning format ASAP.
Thats what i think is the reason why theres no live feed anyway