Pi doesn't work that great, power consumption is still several watts, too much for batteries to be cheap and compact if you want a day or two of backup, plus se

Pi doesn't work that great, power consumption is still several watts, too much for batteries to be cheap and compact if you want a day or two of backup, plus self hosting in general is very much enthusiasts only. Android does what Docker does while remaining very low power, because it gives you one standard API level, rather than some minimal syscalls and you have to bring all your own libraries right in the container.