Sick days are not “offered” by employers. Sick days are prescribed by the doctors and there is no upper limit. After all, your sickness will not disappear just because it has been N days. That's at last how it is in Poland.
Sweden has 14 sick days no questions asked before you need a doctors note. The German way of having to call your doctor for a flu note is a little odd to me. You do loose the first day's pay (the meme is that too many people were off sick when there was a world cup finals or something), and then 80% pay.
This is not accurate. In Germany, you usually only have to get a doctor's note at 2 or 3 days, if youre only sick for a day or two you don't need one.
And there's an unlimited number of sick days. As long as you have a doctor's note, you still get paid, up to some ridiculous limit at which you might have to get government support instead.