Comments by "LoneTech" (@0LoneTech) on "Samsung trolls users with horrible self repair program, $206 cellphone battery!" video.

There's one reason: Batteries will swell a little during their lifetime, and that means you want to leave them some margin, without letting them rattle around. Adhesives are a simple option to achieve the latter constraint. Not necessarily a good one, mind. The traditional method involves a mechanically constrained frame integrated into the battery pack. In the eyes of these manufacturers, replacing that with glue is a win/win/win scenario: cheaper to build, negligibly lighter or smaller for advertising, and harder to repair. For customers/owners, that's loss/illusory/loss. For society, that's all loss; there's nothing to gain in making the insanely rich marginally richer, nothing to gain in making tools break (aside from actively damaging ones like farting cars). It's environmental crimes for the sake of greed.
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@jb5631 S5, all the same features and water resistant, 8.1mm (and that thickness difference vs your modern sample is all the raised bezel to protect the screen). That's pretty much the turning point. Last I checked the only sane model Samsung had on offer was XCover. GSMArena lists the S3 as 8.6mm.
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@kornaros96 That just goes to show it's not even the adhesive that is the problem. It's that Samsung won't sell you a battery without gluing a screen to it first.
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