Programs like Sony Vegas Pro require 16Gb if editing 4k videos.
3d application Poser requires a lot as well.
Another thing to consider is, RAMDisk, and boy would I love to have 32-64Gb of RAM, install a game on in & run it VIA the RAM = faster than SSDs but it is volatile memory so.
Even for video editing, conversion, that RAM can be used up.
Whilst 8Gb will run most things, if you have a partner like I do who is allergic to the 'X' / 'CLOSE' buttons on every single application she opens, then 16Gb minimum is a must!
(lol, spending 5 mins just closing everything down before using my PC again is a daily occurence)