what if they change it while i am walking to the counter @t…

I bet they will have some delay or time frame of at least one hour, where the old price counts.
They probably won't change it more than once a day.
I am not a friend of electrifying everything bit it kinda makes sense.
A lot of time is needed to adjust those prices manually.
And in the current setting where products are getting more expensive each month due to inflation, wars and other bullshit they have to spend more and more money on adjusting those prices accordingly by hand.
Interesting with regards to "resource-event-agent" model and "triple-entry-accounting". Would kinda make sense to use blockchain on the backend.