I would bet you good money it was driven by some sort of rel test (drop, vibration, etc.). Glue can be a lifesaver when the design isn't passing. No manufacturing engineer will want to add an adhesive step to the assembly just to make things more difficult for end users.

2014/2015 MBP - The battery rattles around inside if not glued in place. Sometimes it is needed.

> It's meant to make end user replacement of the battery as difficult as possible.

Any difficulty they add is additional difficulty for the thousands of Apple employees they hire to replace the batteries, so they definitely don't add it just to make it harder.

Don't they charge for replacing it?

They do, but they could probably charge the same and pocket more without all the glue.

> Do you use your laptop in the rain ?

No but I use it next to glasses of water?

> Do you use your phone in the rain ?

When I have to. I walk my dog in a rainy city.

Edit: do you use your desktop in the rain? Maybe I’m missing a use case I don’t understand. Because so far we’ve ruled out any water-tolerance cases I can think of.

Water resistance =/= waterproofing.

Also, the keyboard and chassis in a Macbook are neither water resistant or waterproof.

> Water resistance =/= waterproofing.

I know that but don’t understand the point of distinguishing here. Waterproofing a battery achieves water resistance. In either case the claim was that it isn’t applicable for their portables.

> Also, the keyboard and chassis in a Macbook are neither water resistant or waterproof.

I’m still not understanding how this distinction matters. You claimed waterproofing wasn’t applicable to these devices. How does saying it’s not done well enough support that? Are you just arguing to argue?

Tell me why, in any circumstance, waterproofing a battery is where you'd stop.

You still need to waterproof the circuitry, the connectors, the components like the screen.

The original point was thus:

The argument for making a battery non-user-serviceable and glued into the device (as it is on the iPhones) was to retain waterproofing/water resistance.

THIS DOES NOT APPLY TO MACBOOKS YET THE BATTERIES ARE STILL GLUED IN.

Okay I think I better understand your point but I think it’s just a logic error.

If I understand, you’re saying the inconsistency of waterproofing one part and not waterproofing others suggests insincerity of the stated waterproofing motivation for the battery.

There are two (related) things wrong with that reasoning:

1. It assumes that any kind of water protection must be holistic to be sincere. This rules out any notion of prioritized iteration. It’s like saying (sorry, car metaphor incoming) seatbelts aren’t a real safety measure because other parts of the car haven’t been revised for the same kinds of risks seatbelts prevent or mitigate.

2. The batteries we’re talking about are substantially more fire prone when exposed to water than the rest of the device. That alone justifies prioritizing water safety measures for the battery ahead of any other component.

I’m confused. Why would water proofing be less applicable to a (or their) laptop products?

Keyboard and chassis isn't waterproof on Macbooks, thus, the common argument for glued in batteries on other Apple devices (iPhone) in that it aides with waterproofing is rendered moot when it comes to Macbooks.