Startrek: Impulse Drive and escape velocity

I read many sources and understand that impulse drive can be very fast. A quarter of impulse can be way faster than the escape velocity on Earth 11 km/s or on the Sun 600 km/s. If so, suppose impulse drive can be used within planet's atmosphere and the starship is at the surface, it can go to space without the help of any propelling rockets. Also, it can escape the gravity force of many stars. All of these can be done by impulse drive only. Am I correct?

Does it mean what make starships to have planetary landing capability are thrusters, struts, and dampers? All relate to help the ship land, not propel the ship to space.