Earbud Headphone Covers?

I have a pair of earbud headphones that came with my iPod. They came with two fabric covers for the “bud” part of the headphone - what’s the purpose of these? I can’t notice any difference in sound quality with them on or off - are they for protection of the ears, protection of the headphones, or what? Apple’s pictures of the headphones always show them without the covers - why are they included at all?

I am not sure, but I think they might be to either be more comfortable in the ears, or to fit better.

My boyfriend has an ipod and the earbuds won’t stay in his ears without the pads. I also have earbuds and I don’t wear the pads because they hurt my ears.