The short answer is "yes" - every experience you have working with a community of writers will teach you more about the craft of storytelling. For any workshop, a great deal of your progress will depend on the time and effort you devote to your writing - generally speaking, writing students who write a lot and keep an open mind will benefit a great deal from the feedback a writing workshop provides. In some ways, online workshops are better suited to the busy schedules that many of us keep, but the lack of personal interaction can take away from the motivating energy that comes with sitting in a room full of writers.

This said, some workshops will be more beneficial than others. Depending on your interests and current writing ability, some teachers will be better suited to direct your progress. It's important to find a workshop that makes you want to write more - the feedback should give you a sense of what your doing well and what you need to imporove. You want targeted, specific feedback, both from your instructor and from your fellow students. Ideally, the workshop will help you not only write better stories, but to better understand the components of what makes a story good.