It's equivalent to you helping him with a loan, and the ultimate repayment person is you. If he can't repay the loan (to put it bluntly), the loan company will look for you because you are the borrower on the contract.
Second, why do people need my household registration book and ID card to buy my house with a loan?
I can't.
You need to be present to go through the formalities of buying a house. And at least have a real estate license!
If you don't come in person, you should issue a notarized power of attorney and entrust others to handle it.
Without real estate license and power of attorney, it is impossible to sell a house only with ID card and household registration book.
Why do people who buy my house need to use my ID card and account loan?
Of course, don't guarantee anyone casually. The buyer shall fill in the mortgage loan application form with the bank and provide the documents that must be submitted according to the legal documents such as ID card, income certificate, house sales contract and guarantee. After passing the examination, the bank promised to issue loans to the buyer.
And according to the house sales contract provided by the buyers and the mortgage loan contract concluded between the bank and the buyers, the real estate mortgage registration and notarization will be handled, and the bank will directly transfer the loan funds into the bank account of the selling unit within the time limit stipulated in the contract.