The value of the ?v parameter is 2.5. Unfortunately I don't get any results of the query but when I change my filter to FILTER(?v > 10.0) I get the triple with the 2.5 value out of the DB.
You would need to set the data type to a number type if you want them compared as numbers. When talking straight string comparison, “2.5” > “10.0” because “2” > “1”