> I think Kirkland batteries have less capacity than the premium brands

If you're comparing alkaline to alkaline, it's simply not true. The two videos I linked showed people testing it.

> Also the point of lithium batteries is that they don't leak, not that they last longer.

Well, they DO last longer by a significant margin. Again, this was tested in the second video I linked. The description in the video has a link to the spreadsheet of their data: https://docs.google.com/spreadsheets/d/1KwTt0lu7_aytity4IE3S...

Kirkland Alkaline was on par with the Rayovac Fusion+ and Duracell Powerboost. Only Rayovac Fusion was noticeably better (oddly, the non-plus version was better), and even then, it's not significantly better considering the price.

In terms of dollars per mAh, Kirkland is #2, only behind AmazonBasics.