The energy efficiency is an excellent point.
Ultimately I am still extremely leery of the apple lock in factor in general and their arbitrary rulings of what is and is not okay within the garden.
I am still pretty upset and maybe even somewhat traumatized about all the previous times they've fucked me over in scenarios like this. It starts out great and then gets ruined.
edit It looks like I've hit the HN rate limiter, so I'm merging my reply:
Unfortunately I can't go into detail about these scenarios because I don't want to get into trouble with my employer. Suffice it to say that I no longer place trust in Apple keeping anything of value "open".