I'm not sure I understand this rationale.
Are they paying your loans for your directly, or are you getting a "loan repayment bonus"? If the former, I guess it's tax advantageous for you, but if the latter, it's going to be taxed at whatever your (presumably top) tax bracket will be. So in that case, it's just moving money from one pile to another but it's all the same amount of money. There's no magical tax protected category of compensation for you as the recipient. Your employer may be able to avoid paying their half of your payroll tax if they pay it this way, but you're still going to have to pay the man.