First time I've seen Jackery offered at Costco

My thought is that the Jackery and their ilk are overpriced batter/inverter setups. It certainly will work for someone who wants an all-in-one solution that isn't as good as a DIY solution. The $1150 price is certainly closer to what one would pay for a DIY, but with no real information about the capacities of the Jackery, it's hard to say.

Personally if I wanted a battery backup, I'd source the batteries and inverter myself. Lithium batteries are certainly becoming less expensive.