Kitchen toys are fine things -- I have several of them. But for them to be worthwhile to me, they have to (a) do something I can't otherwise do, like the Anova, or do something I CAN do, but do it much faster/easier/better/more efficiently (like the stand mixer or the food processor).
I don't see the cold brew system being any easier or more efficient than my Chinese carryout soup containers. And when they get stained, it's no big deal, as they've become single-purpose containers, and when they get too disgusting-looking, I chunk them and grab two more. (We order a lot of Chinese, and the local Thai and Indian places use the same containers.)