I also noticed that. When I asked support I got this answer.
Please allow me a moment to check your request. Thank you!
I completely understand your perspective. Being able to download the Airalo app on GrapheneOS through the Play Store would definitely make things easier.
Right now, though, this kind of access is limited due to compatibility and distribution restrictions that are outside our control. Since this falls beyond our scope, the best next step would be to reach out directly to the GrapheneOS support team. They might be able to offer more insight or workarounds specific to their platform.
We really appreciate you flagging this, and I’ve passed your feedback along to our team so it’s on their radar for future consideration.