Comment limited resources are often an issue, even now (Score 1) 637
There are plenty of places where you can't just add more memory...embedded devices in particular. Your phone is limited to 2GB of RAM, and you really don't want any one app chewing it all up. Raspberry Pi, Arduino, BeagleBone, etc. are all relatively limited in terms of resources and to use them efficiently you need to be careful.
Even on really beefy virtualization hosts with a couple hundred GB of RAM, you want to be able to dedicate as much of the resources as possible to the guests, not the host management software--so you need to be able to put strict limits on how much memory the host itself will use under any circumstances.