I am not too sure how I feel about these.
I do think it is a nice concept, but I don't think I would use one. One of the reasons I purchase Hermes is to be able to see the gorgeous interior. It is another one of those finer touches that other bags do not have.
It actually makes me happy each and every time I look inside at the detailing. Sure, I worry I may scratch it or something, but that is part of usage.
I suppose if I had several birkins and I do change bags a great deal it may be nice. Right now, I am not fortunate enough.