[mcrae]

Because its unambiguous -- DD-MM-YYYY could be confused for MM-DD-YYYY

[jacquesm]

I personally prefer to spell out the first three letters of the name of the month to reduce ambiguity, this works well across all regions in the world I do business with.

[joering2]

How can you confuse 31-12-2019 ?

[yongjik]

Unless you plan to use one format until 12th of each Month and a different format between 13th and 31st, your objection doesn't seem relevant.

[NullPrefix]

10-11-2019 and 11-10-2019

[loco5niner]

Obviously you can't, because you cherry picked a non-confusing date.

But you can easily confuse 01-02-2020 or 03-01-2020.