When the removal of one and two cent pieces actually happened in Australia (1991), all the details were distributed in a pamphlet of just four pages. That amount of information is probably about all people need, literally just a document with some guidelines!
In some states, there's legal uncertainty for retailers that operate without pennies. Planning and forwarning likely would have encouraged states to amend laws to provide for penniless retailers. Uniform nationwide rounding could have been an option, interstate commerce and all that.
Some sort of plan for the pennies themselves might be nice, although maybe some sort of plan could have helped pennies circulate more, reducing the need to mint several billion pennies every year.
https://en.wikipedia.org/wiki/Americans_for_Common_Cents
They care more to keep the cent than normal Americans, who ultimately pay for its cost of manufacturing, care to get rid of it. So they'll always win a careful, deliberative process; because they'll show up for the cent _every time_ this comes up. And everyone else gets mildly shafted for no reason.
But yes, our system is biased towards those with sustained focus. That does lead to some wrong decisions, but it's probably better than a system biased to action, or biased towards chaos.
It also probably wouldn't have resulted in any actual action. The problem proponents of "unpalatable and unsexy planning work" confront is that their approach is immobilized by its own weight. Analysis, bikeshedding, and litigation destroys the ability to actually do anything.
It is always best that important government moves are done in public, with processes that are replete with discourse and understanding, instead of with surprises and confusion.
Ideally, the government would had resolved the (present-day, recently-introduced, inevitable, foreseeable) conflict with SNAP benefits and come up with a single-page, large-print summary that uniformly defined how rounding at the checkout counter works in ways that regular people conducting regular transactions would be able to comprehend and follow.
These details certainly all need to be figured out at some point, and sooner would be better than later: We should have started figuring it out years (perhaps even a decade) ago.
Unfortunately, we did not take that path.
Discontinuing the penny could have been a very orderly nothingburger wherein everyone (on all sides of the cash register) knew exactly what to expect, and exactly when to expect it. But but we didn't do it that way.
So instead, we now we have an element of surprise and confusion instead of simplicity.
(But that's OK, I guess: After all, that's just an aggregate of many millions of little inconveniences, instead of some somewhat larger inconveniences for a few people in advance. Their time is clearly more important than yours is, or mine is. All hail the chief.)