I don’t think the stickers void warranty in Europe, they have to prove that the water damage caused that exact failure. So water resistance is actually nice in that sense, because it also means their product probably failed.

But to respond to the first part, it’s just planned obsolescence. Why design something that needs to be fixable, if you can, well, just not do that. You don’t have to design or test opening the case, how it feels to put the battery in. How durable the closing and opening is.

So many problems are just gone, like “does the back get loose and fall off if you open it too often?”

People underestimate how much cheaper it is to not have to worry about user operations and error, you cut out any need for usablitiy testing and design. They are just being cheap and trying to sell it as “cool design”.