I think the point is that breaking it up makes the cost more palatable. It's also easier to convince people to spend a bit of money for people they care about than a bunch for themselves that they don't strictly need. People also often struggle to think of gift ideas for birthdays.

True, but you're still buying an entire battery yourself in the course of a calendar year.

I love the spirit behind this but it's strange advice. I consider myself lucky to have a healthy roster of adult friends, and I still think getting 16 of them to spend significant money on each other's birthday would be a big ask to pull off.

Best gifts are sub $5 and from a thrift store, like a funny shirt or mug.