do you think stable coin can bring about the desired change in the fluctuation in the crypto market?

At least they can, they will contribute to increase the total market cap of the market.

What is stable coin in the first place?

It has a stable price which is $1 but it still moves a bit from $1<-> $0.99 or few lower cents.

If we dont fully know the advantages, the acceptance may not be much. what is your thought on this?

is it not "undermining" them if every exchange launches their own? is there any reason for it? Huh