I've read that, but it really depends on the bug. A simple console.log would catch it easily. I think you need debugging skills in FP right?
I don't always prefer concise code. It means that I have to keep everything in my head, what the function does exactly.
So what I miss is real use cases. Would you write a video editor in FP? Would you make Quake 4 in FP? Is it good for Todo apps? CLI apps maybe? Or is it best for 50 line microservices?