I feel like this might work in a big way for them.
Friday nights weren't a death slot because people were going out. It was because families would only really watch one network all night. Look at ABC in the 90s, or CBS in the past so many years. Anything on another network was doomed to fail. Eventually, the networks knew this so they'd banish shows they canceled/were about to cancel to Fridays to either burn off the remaining episodes, or to "prove" that nobody was watching them, justifying their cancellation.
I think CBS is still king on Fridays, but I can easily see the WWE taking a bite out of their viewership. What do you think is more appealing to networks, advertisers, and viewers? Cop dramas or a live "sporting" event that appeals to the entire family but is skewed more towards the demographics that have more disposable income? You might lose a good chunk of the bookends of that 18-49 spectrum, but the ones left have a lot of money to spend.
I could be entirely wrong, but I just can't see a situation in which the WWE doesn't benefit from this.