Currently the date picker macro uses the dd-mm-yyyy:

If you configure confluence to use a different time format, like mm-dd-yyyy, the macro will still uses the dd-mm-yyyy.

I know that if we manually select the date you want the macro will works fine, however if you are used to type you will write the date you want instead of selecting you will end up writing a wrong date since you are used to a different format.

It would be nice if the macro could use the same format as used by Confluence so customers that are used to write and uses a different date format will not need to worry about that detail.