I am still not sold that e.g. using an arena as a scratch space for real-time frame rendering of the scene is worse than refcounting all of the temporary data,

I am still not sold that e.g. using an arena as a scratch space for real-time frame rendering of the scene is worse than refcounting all of the temporary data, especially if the workload fits comfortably into the available memory. Also, generations are a thing, so no need to "waste several decades of your life". And why is that metaphor applicable anyhow? Why not something like "stop constantly opening and closing the warehouse door during the work, and reinventorize it once a year instead of making a note every time you take something out of it or put something back in it" instead? Anyway, thanks for you time and exchange.