Tenerife is a practical winter escape from the UK because it combines a relatively straightforward flight with a real change of scene. You are not guaranteed a beach day every day, but the island's southern resorts often offer bright, comfortable conditions when home feels cold and dark.
The useful distinction is not simply Tenerife versus the UK, but south versus north, coast versus mountains, and a relaxed resort week versus a more exploratory trip. Pick the base that suits your pace and winter can be the island's most rewarding season for walking, sightseeing and long lunches outdoors.