Discounting bills and loans are both financing businesses and bank assets, so A is wrong. Their financing bases are different. Discounting bills is based on commercial bills, while loans are based on the credibility and repayment ability of borrowers or guarantors, so statement B is correct. The parties involved in bill discount include banks and discount applicants. And the parties to the loan also include banks, borrowers and guarantors, so C is correct. The discount interest of bills is deducted at the time of discount, and the loan interest is charged monthly or quarterly after the funds are used. Interest is charged in different ways, so D is wrong. Therefore, this question chooses BC.