I think this has to do with a mixture of fear of failure, having "smart" be part of your identity and having somewhat of a fixed mindset instead of a growth min

I think this has to do with a mixture of fear of failure, having "smart" be part of your identity and having somewhat of a fixed mindset instead of a growth mindset. The procrastination protects your self identity because you can discount failure as having not tried that hard. It's better to keep your identity small and value continually learning over "being smart".