I am occasionally using a Google burner account with sandboxed Google Play in a secondary profile on my Pixel. Now I wanted to make an in-app-purchase and thought, it would be a good idea to try out a gift card, as described here and there https://discuss.grapheneos.org/d/3718-sandboxed-google-play-store-use-guide/2. I bought a 5-Euro-card.
While my Google account has hardly any information on me, Google asked for my name, address and phone number during the redeem process, i.e. setting up a payment account. I aborted this, because I don't want them to have that information. Lesson learned, 5 Euros lost.
I am writing these lines because some users seem to have had problems, Google not redeeming gift cards and asking for further info because of "inconsistencies". Maybe those users then entered names, addresses and phone numbers that didn't exist and Google does some kind of plausibility check? Google might indeed have good reasons to do so, to stop criminals making use of gift cards.
Anyhow a gift card seems not to be an anonymous way (for privacy reasons) of charging your payment account. At least not in the EU.