The article I read said that Dazn cost USD$19.99 a month and will be approx $35 for Australia.
https://www.finder.com.au/dazn. I think it started off at $10 a month but doubled last year.
I'm sure that Dazn will eventually take over those sports in Aus, but for now they don't have the rights. So unless they pay Bein Sports for them, and Optus for EPL, they'll have to wait to get them. They will only have UCL/UEL to begin with, once they secure that deal at the end of next season.
I don't think the A League can wait for that to happen. So it might be better to tie itself to Optus and the EPL for now and then move to Dazn once it has some content and the pricing is a bit better.