I like that it's easy for us designers who aren't always in front-end developer roles, but still need access when we are working with them throughout our projects (and vice versa).
It makes collaboration so much easier! The layout isn’t perfect - some things could be more easily accessed from one screen instead of having multiple tabs open across different screens/tabs or files within each tab / window -- however this is something you get used too quickly as well :) We're using Zeplin at my current job because sometimes there just needs to me someone else doing what they do best while i'm helping other people out around their jobs which doesn't happen often enough due to time constraints etc..