On one you claim that ARPA will share data b/w different parties and on other side you saying parties can still maintain privacy also? Dont you think they both are contradicting each other?
No they are not.
ARPA enables bank to join the compute for risk metrics for borrowers without disclosing borrowers account info to any other party. Traditionally that was not possible but ARPA made it a reality, thanks to MPC. So now banks have better picture of borrowers and no bank is shy in disclosing borrowers info to the pool.
Theoretically that looks fine but do you have any proof of this use case? that how banks are doing this?