To summarize, when using TEX, users still maintain control of their private keys and do not need to share them with the exchange. The ERC-4337 social recovery method is an additional security layer to help users recover their wallets in case of lost private keys, ensuring a more user-friendly and secure experience.
I think I kinda understand you now, you mean that using private keys in TEX is not necessary, but (if the user wants) TEX can provide them with an extra layer of security by using ERC-4337 social retrieval.
Of course, TEX will not be able to access the private keys of users, but here another question arises, where will the private keys of users who choose this method be stored? Also, if TEX is hacked, will these keys be safe?