As mankind moved into space they faced an alien and hostile environment. While some dangers were immediate (vacuum for example) long term health risks were linked to zero gravity. The first space explorers made do with constant acceleration when they could, centrifuges when they couldn't until gravity control was perfected. Modern spacecraft can now have their decks oriented independent of the direction of thrust. This allows ships like a Scout courier to thrust along its long axis and still land on its belly allowing for greater stability.
Most people just take the comfortable standard gee they enjoy for granted and indeed most ship designers don't get fancy with the grav plates opting for comfort and familiarity but some people do get a little extreme in some of their designs. Some ship captains also get very creative using their grav systems. As a courtesy most ships carrying passengers will gradually change their gravity from their point of origin to that of their destination to let their passengers adjust.
While grav plates are power hogs they themselves are not terribly expensive compared to jump drives and thrusters. Quite a few ships place grav plates on their outer hulls. This allows crew to affect repairs or maintenance in deep space or orbit without the penalties of working in zero gravity. It has the added advantage of crew and tools not flying off into space.
At least one pirate vessel used a gravity field generated from its hull to pull dust and debris onto it to provide camouflage in an asteroid belt.
Some crew have used their gravity control to help delay or repel boarders by increasing, shutting down or oscillating gravity in corridors to disorient attackers. One free trader, being boarded via the cargo deck reversed gravity in the entire hold except for a 3 meter square area the defenders occupied. When the pirates suddenly slammed into the overhead they were easy targets for the defenders who bought time for their ship to make repairs and escape.
The crew of the unarmed free trader Marco Polo used the grav plates on her hull to create an ad hoc weapon system. After a trade deal in a remote outpost went sour several crew were beaten by locals and the ship's captain decided to follow the better part of valor. Before he headed for orbit he flew over a local landfill and turned on the ventral grav plates attracting all manner of offensive debris to his hull. Flying over the town the captain released the debris onto city hall in protest. When he was called out for this behavior he replied that those locals got off easy as the dump was next door to a scrap metal yard.
Needless to say dropping gravity in your cargo bay is a quick way to move cargo modules inside and about. Just make sure your crew knows what they're doing. Those modules might weigh 50 kilograms but still mass a ton.
Some ships drop the gravity below access hatches to other decks. Instead of climbing or descending ladders crew merely jump or drop safely. This is not recommended for areas used by passengers. Indeed some ships dispense with mechanical lifts instead using grav control to move their lifters.
Having zero or lowered gravity at your beck and call is a valuable tool for medicine. Many patients like burn victims can be kept relatively comfortable in a zero gravity bed. It allows disabled passengers and crew to live and function normally. On heavy gravity worlds colonists may live their lives in areas of grav control for health reasons.
A final note: Shorty Stevens, engineer on the Seeker class Nugget, lost his legs in a mining accident. When he couldn't afford cloned or cybernetic replacements the rest of the crew set the ship up for zero gravity (except for their quarters) using hook and loop fasteners, tethers, and cables and kept Shorty on to earn pair of new legs.