The future of this elegant and proven system was put in jeopardy last month, when Google unilaterally decreed that Android developers everywhere in the world are going to be required to register centrally with Google. In addition to demanding payment of a registration fee and agreement to their (non-negotiable and ever-changing) terms and conditions, Google will also require the uploading of personally identifying documents[^regid], including government ID, by the authors of the software, as well as enumerating all the unique “application identifiers” for every app that is to be distributed by the registered developer.
If it were to be put into effect, the developer registration decree will end the F-Droid project and other free/open-source app distribution sources as we know them today, and the world will be deprived of the safety and security of the catalog of thousands of apps that can be trusted and verified by any and all. F-Droid’s myriad users5 will be left adrift, with no means to install — or even update their existing installed — applications.
I think you can set up apple pay on an apple watch and use it offline. So if you are fine with getting a cheap iphone to set up the watch could be a convenient way to only have to go around with a phone and use the watch to pay for stuff. Multi devices seem the best route for those who need functionality moving to custom roms might not offer.