Agree this makes sense, but the big difference is that while checking in can be automated (except international flights), the acceptance of baggage must be done by a human. Therefore incrementally the saving to the airline and tone savings to a pax, would only be marginal,unlike the issuance of electronic boarding passes. Get rid of the human factor in baggage acceptance, and I am onboard, otherwise it's a nice to have, or take a picture of them w your phone.