A question I've always asked myself is "why do we have to play all 30 rounds in group stage?".
I'll try to explain my point of view and obviously, feel free to give yours!

So the first answer everyone would give is "because of the round average". But my answer to this is what's the difference between a 30 rounds average and a first to 16 average?
If we got team A, B and C with A being better than B and B almost equal to C (A > (B ~= C)).
With 30 rounds we'd have like:
TEAM A 20-10 TEAM B
TEAM A 30-0 TEAM C
TEAM B 15-15 TEAM C
There we obviously see that A > B = C with TEAM B maybe a little bit better than C. Games will long 1 hour or so and TEAM A will need to play useless and how boring rounds just to reach the 30 rounds limit.

Now if we'd stop at 16:
with A > B = C it would certainly be this way:
TEAM A 16-5 TEAM B
TEAM A 16-0 TEAM C
TEAM B 15-15 TEAM C.

So what did change there?
First. Round average is not that different (of course i've chosen the score myself but if A > B = C proves to be true, round average would certainly be in that shape). Now we see that TEAM B has a better (or let's say less worse) round average than TEAM C. So A is first with B right behind and C 3rd and out of the tournament.
Second. Games would take around 30 to 40 mins or maybe 1 hour if it needs all 30 rounds to be played (16-14 or 15-15). So all what can happen is a gain of time.
Third. TEAM A no longer needs to play boring rounds against little teams.

So let's sum it up:
There are only advantages (in my opinion) in only playing first to 16 rounds instead of all 30.

I'm all ears to any constructive opinion !

seriously i wonder it to

Fist of all it's because of ROUND DIFFERENCE. So :
1.TEAM A (20-10 , 30-0 = 40 RD)
2.TEAM B (10-20 , 15-15 = -10 RD)
3. TEAM C (0-30 , 15-15 = -30 RD)
And ur Theory is just failed.

Btw u can quite cs/stream and don't watch those "boring" rounds.

and with first to 16 its:

1. TEAM A (16-5, 16-0 = +27)
2. TEAM B (5-16, 15-15 = -11)
3. TEAM C (0-16, 15-15 = -16)

What's the difference? And what if I am in that TEAM A i'm talking about? Because that's it.

just cuz if u lose first 16 rounds in a row u can minimize ur RD by winning other 14 rounds. And the RD results will be more exact after 30 rounds.

Well why not change it to "You had to put that 14 rounds BEFORE they reached 16"?

dunno. i don't care about it at all