you just compared buying a charger to replacing the battery. Also, I am sure if OP wants to replace the battery at a 3rd party store, they could. It’s been 7 years.
The point was that the manufacturer is still willing to produce and sell new replacement parts that are officially advertised and supported for that old of a model, instead of refusing to. I didn't have to guess that it would work, it was on the product page, and they would have treated it as a warranty issue (under the charger's warranty) if it didn't.
They also still have a page on their website documenting current battery products that work with this exact model, including one battery model that can be installed inside the machine like the original one. It's a very different attitude than Apple's.
They also still have a page on their website documenting current battery products that work with this exact model, including one battery model that can be installed inside the machine like the original one. It's a very different attitude than Apple's.