why felted wine cozies?

[punkrockmom]

is there a reason why most the patterns im finding for wine cozies are felted?
why felted? 

[ivycircle]

okay, these are just guesses. I am the world's worst knitter,lol.

1. To protect the bottle. Felted bags are more squishy KWIM?

2. To keep the bottle chilled or warm, depending on the wine.

3. A felted fabric is pretty easy to clean.

HTH! Any more guesses,lol.

[punkrockmom]

maybe they think we're drinking while knitting & it will cover up any mistakes?

[hurdles2006]

my guess is that it is because if the bottle is chilled it will sweat, so if the cozie is felted the it won't matter so much.