I feel like that's a pattern I see around here, which is odd because if you'd rather just use javascript that seems totally reasonable without an excuse.
My hope is that it can help early adopters get over the initial debugging barrier, which, despite the hype, is a legitimate concern. The tool can also be an aid for advocates in teaching coffeescript.
Based on that, what would be even more useful still is a way to browse my code from a within the editor itself. Something with say line numbers on some left pane synchronized with the corresponding file section on the right pane.
Some editors already provide a similar feature using line numbers from compilers ; that's usefull to fix syntax errors typically.
https://github.com/showell/CoffeeScriptLineMatcher/issues/13