Good for you, but a risky strategy if your card is suddenly 'misused' by a waiter, or taken by a pickpocket (assuming one's cash is stashed separately and away from prying hands).
'To not take cash' is advice I won't be following, and I've rarely found exchange rates at destination for AUD to be disastrous in Asia or the UK. I never exchange AUD for foreign money in Australia.
Cash can be very handy for small purchases: if buying an AUD5 souvenir or a small amount of fruit at a streetside stall or market, it's not appropriate to burden the seller with extra costs of cards for small transactions.
Not really most of us who travel cashless travel with multiple cards, stored separately. If a pick pocket takes your cash its gone, credit and debit cards come with protection for fraudulent transactions/theft, not to mention PIN. On a TI claim much easier to prove card tranactions than how much cash was on your person.
I travel with Citi-bank debit and Macquarie bank debit cards (never in wallet/pocket together) which both have no fees and the Mastercard exchange rate, IME exchnage places offer higher rates. I use app to move money from linked savings account (online only cant be accessed via card) onto the transaction account thus topping up what is on the card as needed.
I also have a couple of credit cards with me (always leave 1 credit card and 1 debit in the safe with my passport).
I can easily get small amounts of cash if needed, just rarely seems to be needed anywhere. Paying by debit or credit means you dont end up with leftover foreign currency particularly coins which are heavy and cant be exchanged for other currencies.
Of course depends on where you are going, if going to Cuba you need cash. UK or USA not necessary at all.
YMMV but over past 5 years years I travelled to UK, USA, Fiji, Spain, Portugal, Singapore, Hong Kong, Croatia and Bosnia all without any local currency in my wallet when I arrived and had no issues whatsoever with using primarily cards and getting a small amount of cash (i reckon less than AUD $100) if needed.
Better that spending money is earning interest until I spend it rather be stored as cash.