Some people don't like rebloomers because they are
too busy to give them the care they need. They need extra water & fertilizer
to rebloom. While the irises beside them would not like extra water &
fertilizer and might rot with the extra un-needed care.
Also, until recently, most of the rebloomers did
not have as perfect a form as the non-rebloomers.
You are correct that "self" means that the
standards & falls have the same color. However, if it has half marks, the
standards & falls would be different and therefore the iris would not be
considered a "self". The beards do not count.