Enable Tab for navigation through Description, Labels and Billable fields, in order to enable keyboard-only time entry which is quicker.

Example: Type your hours tracked > Tab > type your description > Tab > select time label(s) > Tab > toggle billable on/off > Enter (to submit). At any time in that process you could hit enter to submit, for example after typing the description because you don't use labels or billable hours.

Could also allow the date picker to be selected by Tab.