I'm an Australian privacy-obsessed Fastmail user, and use them for my family domains and all our primary email. I'll keep using them, because email isn't private in the first place. Any more than snail mail is. Both can be intercepted and read by authorities without you knowing.

For secure communications, you shouldn't be using email in the first place, so these new laws don't change much in that regard (in my understanding, I'm still catching up on the new laws because I have limited internet access right now, I'm happy to be corrected).