why should the law give legally binding effect to those things as we know contracts?

Question

Any answer will be appreciated

Answer 1

Because to do otherwise will inhibit commerce.

If you can't accept a delivery before inspecting it without risking it being an empty box, everything slows down while every box is checked.

If the law won't enforce a contract, you risk having your fixed rate mortgage becoming variable because the lender wants to, or you risk your loan not being paid because the law won't enforce a defaulted loan contract.

Commerce would be all cash, caveat emptor, no warranties without the law.

and besides all that, why are you questioning one of the few things that the government does that it actually should do?

what do we even need government for if not to enforce contracts and protect from other violence?