It's because the glued the damn batteries to the top case, which is also the part which everything else is screwed onto. So replacing the battery either require

It's because the glued the damn batteries to the top case, which is also the part which everything else is screwed onto. So replacing the battery either requires replacing the whole top case (A LOT of manual work, and more costly in parts), or engaging in the potential fire hazard of removing the glued battery.