What happens when Facebook closes the dummy, fake account you've associated with that device for not being a real person? Do all of the purchases you've made also get blocked?
This was discussed in depth in a previous discussion in the topic, but your assumption that it's trivial to create a fake Facebook account for this is wrong. There may be different experiences but you should assume you'll need a valid mobile number or a valid-looking social graph, or both.
Not just for this purpose, but Facebook accounts in general. If you try to create one without a valid number and/or seemingly valid friends list, chances are it's blocked in no time.
I don't know a thing about Google Voice, but I for one wouldn't bother setting up some fake numbers to create a fake account to use my own hardware.
I recently created a Facebook account with a made up name and a new Google Voice phone number to sell an old monitor and the account was disabled within 2 hours.
I tried to create a work Facebook account using my work email address and phone number and they required SMS verification. I tried all manner of services, even Twilio but Facebook seems to be able to differentiate.
Facebook collects data beyond what you provide when opening the account; they can use that to either detect the fakeness of the account and close it or track its activity to populate your (real) shadow profile, or both.
Just like with radioactive sludge, the best way to deal with Facebook is to not get anywhere near it.
Seems like a dummy, fake, account would provide what you need?
What other concerns do you have?
Legitimately curious.