i'm sure they can find a can opener in any of the houses, so that is kind of a non issue imo.
I'd say "small issue" rather than "non issue," but agreed. And of course if they have a Wal-Mart or a supermarket at their disposal, they can get an opener. It's just another thing they need to keep track of.
Power is among the lesser issues right now. And if they're always going to be in a house with working utilities (those being cut is, I think, a very real risk), well and good. But they're more or less constantly on the move, they need to eat on the move, and most places they might stop would be suboptimal for eating canned food.
Is it heavy, sure, but there really isn't much of a choice is there. Still the better choice to snacks from a convenience store
Of course there's a choice (if a limited choice), and which is better depends on their situation. If they're just going to hole up in the house, and there's a market a block away they can loot, sure, go for the canned food, use the kitchen, eat, drink, and wait for help to arrive.
But that hasn't been their MO to this point, and I doubt that's going to change. They should, I think, hang there for a few days to regroup, recharge, heal, etc., but I fully expect they're going to be on the move again soon, and continue to be for the foreseeable future. And if they don't have any assurance of being able to get food at their destination for the night, or along the way, they need to bring their food with them. Snacks from a convenience store are going to have more calories per unit weight than anything canned, and calories are their most fundamental need at this point. Again, MREs would be better, but still heavy, and limited availability.