Firstly the store accepts Maestro anyway, so this isn't even a debate in the first place. Just buy your ARX with that.
PayPal may be widespread but it's not the de facto standard - everywhere that takes PayPal also takes EMV and in the majority of cases Amex as well - and even worse it is not a regulated standard. Frontier have deemed the risk of using unregulated payment providers much worse than using regulated providers.
On the other hand, Frontier have decided that they should be the ones to deal with holding your billing address even though that is something they could leave entirely up to their payment provider, so this is another case of Frontier just making weird unsupportable decisions after all.
PayPal may be widespread but it's not the de facto standard - everywhere that takes PayPal also takes EMV and in the majority of cases Amex as well - and even worse it is not a regulated standard. Frontier have deemed the risk of using unregulated payment providers much worse than using regulated providers.
On the other hand, Frontier have decided that they should be the ones to deal with holding your billing address even though that is something they could leave entirely up to their payment provider, so this is another case of Frontier just making weird unsupportable decisions after all.