With a virus that escalates exponentially, a week is a long time. If they waited a week, things could have got a lot, lot worse in the affected countries. For example, it is now widely accepted that the week's delay in imposing lockdown in this country is the main reason we had one of the worst infection rates in Europe, for example.
To be honest, I was surprised that they didn't impose it sooner - it has been well reported that the numbers in France have been rising for awhile now. Once again, I think our government are dithering for too long.
There are a number of other European countries whose numbers are well over the 20/100,000 mark that our government are using as the benchmark, that must surely be candidates for taking off the safe list. I certainly wouldn't now be booking a holiday to one of those places. Unfortunately I already have one booked, so I will be looking very, very careful at whether the number is rising or falling before I decide to go.
ECDC Data