what are the debug versions used for?!!

[FS Lover]

I don't use IDEs. (at least since those old days of the DOS compilers/IDEs)
I always debug with classic programming means; mostly, outputting some messages in different places and levels of the program.
Remaining (and usually substantial) task is the (re-)analyzing and thinking about the cause(s).
complementary guesses and tests, etc.

I think these are fast enough for me and cause me to become more stronger and gain more insight about the program (and other programs) and problems (even problems that have no sign at the moment).