The learning curve for sprinkling print statements is easy. The learning curve for using the debuggerer is hard, and provides little immediate benefit. So many people - myself included - don't bother learning the debuggerer, despite learning it providing a long-term benefit.

Between print, Data::Dumper, Devel::StackTrace and Devel::Trace, I've yet to find a case where the debugger gives enough benefit to learn it.