[OT] why not keeping the original column name in catalog after a drop?

Hi all,
when you drop a column on a table the pg_attribute is updated and the
name of the column is changed with an almost fixed identifier that
reports only the original column position:

/*
* Change the column name to something that isn't likely to conflict
*/
snprintf(newattname, sizeof(newattname),
"........pg.dropped.%d........", attnum);
namestrcpy(&(attStruct->attname), newattname);

I'm wondering what is the problem in placing the old/original name
after the "pg.dropped" prefix. I know that the tuple in pg_attribute
is temporary, but what are the possible conflicts the comment talks
about?

Thanks,
Luca