Workshops aren't the only way to conduct discovery, kickoff projects, or collaborate with stakeholders and users. I think they're the best way. These posts go into some of the rationale for when to choose workshops, as well as when not to choose workshops.
Kickoff projects right by choosing the discovery method that fits your team resources and supports your project goals for optimization or innovation.
Dan Brown on how to choose the right methods to craft your discovery phase (from the 2016 IA Summit).