There are a number of really good reasons teachers choose relief teaching as a career of choice. Good pay is probably not one of them, even though you earn more in the classroom than Bunnings.
But there are many reason relief teaching suits.
You are waiting for a permanent job. Cool! What a better way to learn the craft of teaching than to spend a stint relief teaching. Here is your chance to check out another teachers' room, have a look at resources that you could use yourself and experiment with different styles of teaching. Knock yourself out!
Like me, you have retired from full time work and you are tired of tying up the tomatoes again. Seriously I enjoy the interaction of the classroom but after 40 or so years, I don't need to (or want to) work full time any more. I know a lot of teachers who have retired from full time work and now want to use their skills in the classroom in a different way. Relief teaching gives you options to choose the gigs you want (and the ones you don't)
You are too old for McDonalds'. That'll work.
So you are in it for the money. So what? 99.9% of people wouldn't turn up for work if they didn't get paid. Relief teaching is a professional job and deserves a professional wage.
Full time work is not for you. A lot of people find full time work does not suit their lifestyle for one reason or another. Relief teaching is a great option. Full time teaching has its own special demands and some teachers find that relief teaching has some professional benefits.
You ticked the wrong box on your application form.