Just called Citibank to enquire if there are any different fee structures for the Visa vs old Ready Credit card, and guess what? There is! And of course there is no mention of it in the letter detailing the "benefits" of enhancing my account with the Visa card

.
If using the Visa Debit card overseas, there is the standard 2.5% Citibank fee for foreign currency transaction (originally was 1.5% but increased a few years ago) PLUS a 3.3% Visa foreign currency conversion fee! So that would make it 5.8% (assuming they are not compounded) or 5.8825% if compounded!
Needless to say the Visa card is now sliced into many small pieces and distributed among several rubbish bins, and I asked the Citi agent to note my dissatisfaction with the misleading nature of the offer by not mentioning the different fee structure at all.
So a word of warning for anyone else with a Citibank Ready Credit account being offered an enhancement to this Visa Debit card to be sure to check all differences, even those not identified in the letter of offer.