New Zealand took the option of making one dollar equal ten old shillings. No problem that I noticed.
As did Australia. And, within three weeks of decimalisation I conducted the first decimal currency In SW Tasmania, on Federation Peak; a party we met there wanted some extra film I had brought in and could spare.
"Dismal Guernsey" (as it was known in Strine) knocked the swank around a bit because they could no longer price their upmarket goods in guineas but had to use the 'common and garden' dollar.
Regarding Oz slang for predecimal currency a threepenny bit was a trey, a sixpence was a zac (or zack), a shilling was either a dina (pronounced deena) or a bob, a two shilling piece was a florin or two bob (leading to the phrase "bent as a two bob watch"); we had lost both half crowns and crowns by WWII although five bob was often called a dollar until dismal guernsey came in, and a pound was a quid.
These days it's rare to find supermarkets pricing anything with less than "9" as the final cents digit. Because 5 cents (the old sixpence) is the smallest coin in official circulation, 1 and 2 cent prices are rounded down to the nearest zero, 3 and 4 cent prices are rounded up to the nearest 5, 6 and 7 are rounded down to the nearest 5, and 8 and 9 are rounded up to the nearest zero. So you get lots of impecunious people taking the supermarkets on at their own game by leaving their purchases (if they only want a few items) until they have three items ending in 9 cents and taking the reduction of the total back to 5.