Reddit user PrimaxAUS has stated several reasons why they use a VPN, and why we all should be worried about mandatory data retention. 

I have a VPN in place now from my home router and my mobile devices, but not due to porn or piracy or anything like that. I'm worried about how my data and the data of my family will be used in future, primarily by future governments and corporations.With a huge portion of my life online now, I don't know how my views, habits and actions will be judged in the future.

• I don't know if an insurance company will be able to access it in future, and affect my premiums.

• I don't know if a future conservative government will implement a citizen score system.

• I don't know if my browsing habit will get me on a watchlist somewhere (I work in cybersecurity so I probably already am).

• I don't know who will be able to access my metadata in future, because targetted hacks and the resale of stolen data is very common.

• I don't know if the data will be used to steal my identity, and because I can't change my identity I know it's hell to go through.

• I don't know where my data will be allowed to be stored in future or if the protections of today will be revoked.

Ultimately, storing a big pile of my data 'just in case I do something bad' is an wedge issue to push for more control and more visibility into what Australian's are doing.Worst case scenario: Someone like Stalin or Mao would love these kinds of powers and we just don't know that we won't end up like someone like that in future.