For landing hovever it makes things signifficantly easier! You can break full arrival speed from lunar or interplanetary space (successfully done by Apollo missions) with a relatively light passive heatshield & land on parachutes. You can even brek to orbit instead or use the atmosphere to change incliunation of your orbit and other tricks (there are proposals for air breathing ion engines, etc.).
Lack of sufficient atmosphere is what makes landing on Mercury (no atmosphere, need to break to zero using rcoket thrust) and Mars (enough atmosphere to break from arrival speed, not enough to use parashutes or gliders for a soft landing) so difficult .