Would you prefer that on the 29th when the Beta launches proper that it's not working well? Even though I'm not playing H5G at the moment I'd rather they test it out in the wild now than risk the first couple days be a clusterfuck.
343i had marginal to do with the MCC. They launched Halo 4 extremely well. They've had A LOT of time to gear up for this beta. To not give the people who bought their broken-ass game, just a little crumb, like early access, TEN DAYS, to the Beta, is insult to injury.
It's laughable. I'm sure they already had this promotion or whatever you want to call it in place, but I'd have to imagine with how AWFUL MCC has been/still is for some, they would've changed their plans and tried to gain some will back by saying "Hey, we fucked up on the MCC, as a small token of our appreciation for sticking with us, we're giving you early access to the beta. This is just the first step towards gaining back your trust."