This caught my attention as well. With all respect to Halak (and I do think he's a BIG upgrade over Khudobin 2016-7, and over Dobby 2.0 too), I don't think we have the conditions to call them a 1A/1B goalie tandem. There's a pretty big gap between Rask and Halak, IMO.
Are there teams where Halak would be a #1 goalie? Possibly, but thankfully, we're not the Sabres. I just don't see Halak realistically competing with Rask for the #1 spot. Will he compete to keep Rask down to under 55 games like this season? I hope so. But do I want to see Halak regularly playing against strong teams within the division, like the Lightning and Leafs? Hell no. (Well, eating my words a little, as I checked and see that we have a November back-to-back with TOR/VGK. That's a tossup as to who gets which game, especially depending on how Vegas looks.)
That said, Halak probably will be fighting for games a little more than Dobby, and I think that's good for Rask. I just hope that if Halak winds up "winning" a few extra starts, it's because we have an embarrassment of riches in the net, and not just an embarrassment.