Obsessed with Oracle PL/SQL

I received this email from a longtime Oracle Database developer: Why shouldn't we  always use clobs instead of varchar2 in PL/SQL? Memory will be allocated once used so there should not be any overhead always to use clobs instead of a varchar2. There must be a reason, however I'm unable to come up with a explanation. If it is true,  you might say the varchar2 is deprecated, ;-) I had to laugh a bit when I saw this - not because I thought his question was funny or silly, but because it reminded me of what I sometimes say in my trainings. I ask students: Why don't we always declare all string variables as: my_variable VARCHAR2(32767); That way, we don't have to worry about a VALUE_ERROR exception if the string gets "too long". And since memory is allocated dynamically (for lengths above 4000), it won't cause excessive memory consumption. And my answer(s) to this question are: This declaration - especially appearing all over the place - will r...