They do the SQL DATE() work for you, and manage the differences of SQLite.
Your result can be achieved as so:
->whereDate('date', '<=', '2014-07-10')Though the above method is convenient, as noted by Arth it is inefficient on large datasets, because the DATE() SQL function has to be applied on each record, thus discarding the possible index.
Here are some ways to make the comparison (but please read notes below):
->where('date', '<=', '2014-07-10 23:59:59')
->where('date', '<', '2014-07-11')
// '2014-07-11'
$dayAfter = (new DateTime('2014-07-10'))->modify('+1 day')->format('Y-m-d');
->where('date', '<', $dayAfter)->whereDate('date','=','2014-07-10')
->whereDate('date', '<=', '2014-07-10')
