I'm not certain, but I'd think it saves on paying the crew. They are working 16 + weeks less a year, and have to be out by 5 or 6PM each night. No more overtime, no more Saturday tapings, 16 less weeks a year of pay. That's a lot of how they save money from the big budget cut of 2009. The cast of course has been getting less money too, but it doesn't matter to the cast how many weeks they take off. They still get paid per episode. NBC used to own the Burbank Studios until very recently. They sold them off a few years ago, so I'd think they now have to pay rent for the full 52 weeks regardless, since it's the Days studios whether they are dark or not. I don't believe studios 2 and 4 are available for taping anything else during the dark weeks. They did a Facebook Live chat to celebrate the 13,000th episode in January (it was during a dark week) and all of the Days sets were still up, even though they had been dark since November,
It's hard to believe, but it's true! The legend, the greatest of them all, the one and only Barbra Streisand turns 75 today!
Happy birthday to a true phenomenon, the like of which we will never see again.