In message , Martin
Underwood writes

Forgive a naive question, but what is the advantage of Oyster over paper
tickets - either specific single/return ones or a one-day travelcard? Are
Oyster fares cheaper than paper-ticket fares for the same journey (assuming
it's not by NR!)

Yes - considerably cheaper: an off-peak bus journey is 80p with Oyster,
£1.50 with a paper ticket; a zone 1 tube single is £1.50 with Oyster or
£3 without.

Oyster fare-capping means that one day's use should be 50p or so below
the equivalent one-day travelcard price - so, a much smaller saving
there, and no saving at all if the travel includes a national rail
journey since that will normally have to be paid for as an additional
item.

or is the main advantage the convenience of not having to
queue up at a counter or ticket machine before you can travel?

That is another advantage. The current non-acceptance by most of
National Rail in London for prepay/occasional travel is the biggest
disadvantage for many.

--
Paul Terry