Answer: In order to protect the camera lens ;-) Without this cover makes it more likely that the lens scratched because this is curved outwards, unfortunately (not the lens but the version in which it is held)
PRO:
+ Very good fit
+ Weretiger impression
+ Scratch- and stain-resistant
+ Serrated surface is ergonomically in the hand
To clean: Unfortunately, I times a mishap happens; I have accidentally lubricated ball pen stains on the white envelope .... was very annoying because with brush and stain removers pollution did not want to go away.
BUT 2-3 days later nothing was to be seen of them, shell looks like new :-)
Conclusion: For the price (9,95 + shipping) you get really fulfills all demands a very good hard-cover.
5 star quite rightly