I've heard that they were planted (or grew) near monasteries, and as such developed the name. I've often joked that working in them might get you to heaven, or hell depending on which way you're going... (if you believe in that...)
However, I kind of have an appreciation for them, they're almost pretty in bloom, and the seed heads are cool, and they grow in places lots of other things can't... In fact I removed a few large healthy ones a few years ago in a downtown back alley , and they had a great little environment existing underneath... it is one of the few jobs that still haunts me, really they came down for no reason.
oh and maybe you trees in the first pic were trained like that when young, to sort of form an arch.... Cool anyway.