It looks like they increased the gift card amount from $100 to $150, beating this previous deal posted in 2021. They're a member-owned not-for-profit health fund which I have heard some good things about. I have personally not used them before so I can't speak to the quality of their service.
Make sure you read the terms and conditions at the bottom of the page in the deal link. They also give some important information there about how to redeem. E.g.,
To redeem this offer the New Member must email [email protected] with their new membership number (New Member) and the full name and membership number of the Phoenix Health member they were referred by (Referring Member) within forty-eight (48) hours of completion of their membership application.
I also emailed their team to ask some questions about the offer and got the following response, which might be helpful to some of you:
if you were to refer someone to us once you’ve become a member, even if you have joined us with Hospital only, you can still refer others to our fund and claim the $150 digital gift card, but again, the person you are referring to the fund would need to join on a combined Hospital and Extras cover.
Username checks out :)