Hey, here's some background about dates and times:
Dates are stored as type DateTime. This means you always get a Time component with a Date.
Time is represented as the number of milliseconds since midnight of the date specified.
Your time of 12:00:00 AM is midnight, which is represented as 0 in the DateTime instance.
What this seems to indicate is the Date Picker returns a specific Date but not a specific Time, simply assigning the Time component as 0 (midnight).
You cannot dispose of the Time component. It's always considered to be present, even if it's just a 0 representing midnight.
The way to display type DateTime as only a date, or only a time, or a date and a time combination is through formatting.
Do you want a Time component? Maybe a different Date Picker is more suitable.
Don't want a Time component? You would need to apply some formatting to hide the Time component.
Not sure these are the answers you're looking for. But I think they explain what's going on.
HTH