I think it's ok for switching to be hard if the UI is built for productivity. I'm not really a "creative" worker in the most common sense, so I'm guessing GIMP's UI sucks even after you learn it, but I do know VIM is not intuitive at all, yet improves productivity compared to most IDEs/text editors. I've also worked on an application, working closely with our somewhat technical users, and they would suggest UI changes that were often not intuitive, but increase their productivity a bit (less need for using a mouse, less keystrokes/clicks and stuff like that).