Earring backs - REALLY STUPID QUESTION

[PleaseMrsButler]

I haven't really bought earrings since I was a child. Now they all seem to come with plastic/rubber backs in addition toe h butterfly backs. So what is this for?

1. To keep earrings on the card in the shop, to be disposed of once home?
2. An alternative to the metal butterfly back for those who are irritated
3. To be used in addition to butterfly back to make it more secure (cos they seem really tight)?

I think.

I had assumed 1. as well, but I suppose they could be there as an alternative to the metal ones.

No. 1.

I'd always assumed one as well.