Aris, I'm not sure I'm ready to drop my 2 oz of titanium tent stakes, but you are asking exactly the right question that every UL hiker needs to ask about each piece of gear or even each feature on each piece of gear. Why, Why, Why. This is exactly how we got where we are...
Why do I need boots?
Why do I need a framed pack?
Why do I need a tent?
Why do I need a pot?
Why do I need a rain jacket?
Why do I need...a padded hip belt?
Why do I need .... fill in the blank.
Most backpackers that I talk to still assume you need all of these things and a lot more to be safe and comfortable. On my last trip I carried none of them and did extremely well...better then most.
Some items I determine I do not need, some maybe less of, some maybe a lighter version, etc.
Now I have not been wondering about why I need stakes, but I last asked myself why I need 8 stakes. I do notice that Ryan's UL gear list shows 6 stakes. My setup requires 8 stakes so I want to figure out if I can get a good setup that uses only 6 stakes (I use a 5x8 poncho tarp if anyone has suggestions). That being said I would love to drop all 8 if I can do so by just upping my skill.