What is score based arena tournament?

As the title says, I am wondering about what is the difference between 3/0 Score Based Arena Blitz tournament and regular 3/0 Arena Blitz tournament?  I never seen this format before, I also joined one yesterday but couldn't figure it out the difference.

 Also I can't find any link on website about how each tournaments works, rules, calculation etc.

Can somebody just enlighten me, thanks.

There is no difference bro!! i noticed this too but the only difference is details. Chess.com added some details however if they would do it once people will not be able to understand but now they can slowly and slowly figure it out

I think they may still be in testing, but score based pairs similar scores together where normal arenas pair similar ratings, regardless of scores.

Oh no! I guess 500 rated players can't win over GMs anymore. So sad.

One of the reasons for the original pairing system was to allow anyone to win. 

Yes, but if anyone can win then it's a roll of the dice, not a reflection of skill.

Better to have tiered placement i.e. top 3 U800, top 3 U1400 etc.

It's not a roll of the dice. The points still have to be scored, it's just that the impact of rating is lessened somewhat, since the average opponent rating is going to be closer to  each player's rating.

Well, on paper it's random, and I could even make a good argument for why the format should favor very low rated players...

... but from experience I know it doesn't work like that in practice, and anyway, I was mostly having a bit of fun. A new type of arena sounds interesting.