That is exactly what I was saying; don't write to convince that you will be returning; write about YOURSELF and your intent and your goals and your reasons for pursuing the degree and it's benefits to your life back home. I applied with 20,000 CAD for an 80,000 CAD post-secondary degree and I got accepted without an interview call.
It isn't about the money only. I have read cases where people have shown millions in the bank but still get rejected because they try too hard to convince them of WHY they will return and not WHY they're going.
Also, they will go through everything you send their way; they will read every word. Your letter is part of your application and will not be ignored before a decision is made.
Just my two cents.