Is Kamakura worth visiting from Tokyo?
Yes, especially when you want a lighter day rather than another giant logistical production. Kamakura gives coast, temples, walking streets and a softer pace within reach of Tokyo.
Answer
Kamakura is not the most dramatic day trip from Tokyo, and that is part of why it works. It gives you temples without Kyoto-level pressure, sea air without a beach-holiday detour and streets that are easy to wander without turning the day into a transport exercise. Go when Tokyo starts feeling too big, or when you want history and coast in the same outing. It is also a useful counterweight to Nikko or Fuji-area plans: less monumental, more relaxed, easier to fold into a city-heavy itinerary. Do not over-plan it. Kamakura is better when it is allowed to be a gentle reset.