Not entirely sure of the practical value of this, but looks fun, and it’s pretty interesting to learn about the physical changes the glass goes through in the process. I might have to try this just to be able to show off my melted bottle 🙂
Similar trick: nuke an aluminized glass christmas ornament (sit it on something nonflammable.) When the aluminum vaporizes, the glass heats up enough to start melting, and the result is a small but impressive light show which goes through several distinct stages. Makes some smoke in your kitchen though.