It all depends
As a regular visitor to London I love having Oyster. I just need to remember to scan in and out for train/tube travel and with a simple flat fare on buses I only need to scan in. And it automatically tops up so I'm always able to pay the fare (bank balance permitting!)
For urban areas these smart cards are great and simple to use. It *could* (but probably won't) make travelling by First in Bristol simpler and cheaper but in outlying rural areas like Somerset they will have to use scan in and out to ensure they can charge the relevant extortionate fare.
All in all, though, for ease of use (if properly designed) and the fact that it could eliminate the abuse of 'change tickets' by the bus companies I'm all in favour.