ISAs are not loans!
With a loan, you pay interest every year, regardless of if you graduated or found a job. Student loans can follow you for the rest of your life.
ISAs are designed to be affordable no matter what, and they expire after a set time. If you don't land a high paying job, you shouldn't have to pay.
TradeUp exists to help you make it through vocational or trade school, without having to risk private loans. That way, you can get an education worry free.