DAI is mostly collateralized by USDC so there is a lot of overlap in the risk exposure of the two assets.

why someone would colletarize a stablecoin like USDC to generate less stablecoins like DAI? Where id the gain while on a dollar to dollar its close to 1:1 ratio all the time?

It’s not that DAI is over-collateralized with USDC, it’s that among all the different collateral types, USDC is over represented. This Reddit thread provides a pretty good explanation as to what is going on:

https://www.google.com/amp/s/amp.reddit.com/r/MakerDAO/comme...

Here are live stats about dai (and including its collateralization)[0]

[0] https://daistats.com/#/overview

Thank you! Can you possibly explain the difference here between "Dai Collateralization" and "Dai Generated by Collateral"?

In one chart ETH still predominates, but in the second USDC is the largest portion.

answer to your question is here in reddit comments https://www.google.com/amp/s/amp.reddit.com/r/MakerDAO/comme...