Under 3.1 Allocator Interface, there is a great point about reducing wear levelling by rebalancing the B+ tree operations to reduce the number of writes thus extending the lifespan of the hardware. Not much of a concern on the small scale, however in large deployments even single-digit improvements will make a difference.

Sometimes it becomes useful to appreciate the hardware and what it is doing, reminds me of the quote.

* You don't have to be an engineer to be a racing driver, but you do have to have Mechanical Sympathy *. Jackie Stewart