The 717 FCOM allows for the autothrottles to be used if autopilot is off. It doesn't mean that I let it do ALL the work and not monitor the airspeed trend.
Similarly both 777 and 787 FCTM state (identical wording)
Autothrottle use is recommended during all phases of flight. When in manual
flight, autothrottle use is also recommended, however manual thrust control may be used to maintain pilot proficiency.
... different rules for different aircraft.
The 717 is not really a Boeing
and it definitely is NOT a 737.