If I got beer then why would I want water?
I think the point of the original foil idea was that you might not have a pot, empty can or stuff like that with you. It is a bit bulky to put in a pocket as EDC.
The idea of foil as a makeshift kettle seems to have some drawbacks but it is still an alternative to carrying a big pot just in case.

So far it seems that the problem is with thinner and cheaper foil.
I have not found a supply of really thick foil like MSR uses for camp stove windscreens but I have found a few sources now that are borderline adequate.
The windscreen foil seems a bit too heavy and bulky to fold and pack well anyhow.