|I did not read the article but I would think that it should have been stated the other way around. Something like: Manufactures that make laptops with sealed in batteries (presumably) use the best available batteries for a longer overall life span. The money they save on not needing a battery compartment or a rigid battery case can be spent on the better battery. The net advantage for the consumer is a thinner, lighter laptop.|
A battery pack is only as good as the weakest cell in the battery. One other thing I learned a while back with high performance electric radio control (cars, planes, etc.) is that the closest the batteries are matches to each other (capacity, charge rates, high discharge rates, and internal resistance), the better the battery back will perform under high draw rates, quicker charge rates, and longer life span. You are less likely to get a cell reversing polarity, going shorted, or loosing its ability to take a charge. This was with NiCads back then, but the general principals still apply, it just takes more effort to test and match cells so it is rarely done in industry.
You have to be a little bit crazy to keep you from going insane.