In context of the app "Basecamp" I can understand that designing for an application doesn't really require deep design exploration in a tool like Photoshop.
As a user experience designer I tend to gravitate towards Photoshop because I'm designing new experiences for new clients for each and every new project. Without defined guidelines in place, (like Basecamp already has) I need to explore my options.
The design doesn't need to be high fidelity by any means but I think it all boils down to preference.
In closing...
Use whatever method or tool that works for you and quit writing about the pitfalls of any of them.
In context of the app "Basecamp" I can understand that designing for an application doesn't really require deep design exploration in a tool like Photoshop.
As a user experience designer I tend to gravitate towards Photoshop because I'm designing new experiences for new clients for each and every new project. Without defined guidelines in place, (like Basecamp already has) I need to explore my options.
The design doesn't need to be high fidelity by any means but I think it all boils down to preference.
In closing...
Use whatever method or tool that works for you and quit writing about the pitfalls of any of them.