We use Goodly at HireArt. There is no tax benefit - you are right that it has the same net effect as adding to the employee's salary for them to use to pay off their loan directly.

We see it as a nice way to encourage good financial behavior (not unlike how many companies have default retirement contributions). And the fees are small enough to not make a big difference.

I think we'd also be interested in a program that took the money out of people's paychecks for repayment - especially if the issuers would give the employees a discount in exchange for getting a reliable paycheck-backed repayment.