You can pay for iCloud using gift cards, I've done it.I currently have a gift card balance on my account but my iCloud payment gets charged to my credit card every month. I'm pretty sure that's the same for my iTunes Match subscription. I'm not sure you can pay for iCloud and iTunes Match with gift cards. I think hey have to have a credit card on file. Gift cards applies only to media purchases at the moment.
You can pay for iCloud using gift cards, I've done it.
My monthly iCloud payments are currently being taken from my iTunes balance - so it is possible.
My iCloud storage is payed for with gift cards. I have a card associated with my account if I have to use it but thank goodness for swagbucks so I rarely have to. It also paid for my iTunes Match subscription. I assume it will work likewise with Music as it will probably go through your iTunes account.
i got a friends US paypal linked to my iTunes account even though i am using gift cards. i guess thats why iTunes Match has been working in the past and hopefully it will be the same for Apple Music
(i am in germany)
My iTunes Match subscription fee was deducted from my iTunes balance so I would assume it would be the same for Apple Music.