Exactly what was the purpose of non-replaceable rechargeable batteries?

[SaburoDaimando]

Where you couldn't remove the cover of any kind and replace the rechargeable battery pack with a fresh new battery pack should the old one fail to recharge? Especially on expensive game machines and controllers

(Points to the PS3 controller, the PSP Go and the PS Vita)

[KelaniScar]

If the battery breaks, you either have to pay to have it repaired by the company, someone with experience, or buy a new unit altogether. Seems logical from a business point of view. Most businesses don't care about screwing you over like that.

(Or they just want to keep their batteries special.. :3)

[Remilia]

Part of the reason is design. A lot of cellphones these day don't have removable batteries. It's annoying because like said, if it breaks, you need to replace it somehow. (Though some of em you can crack open and replace it manually).
Designing a new piece of hardware isn't easy, and to fit the battery with all the circuitry and able to have an area for removing and replacing the battery isn't easy. They also have to make sure the integrity of the area can't be easily compromised.

It does all attribute to laziness or just technical difficulties that make it impossible. The more stuff you cram in there the harder, especially for small hardware.