All good questions. My personal answers boil down to "no need" (to switch), "see the rest of this thread" (to read what promise Perl 6 might have), and perhaps https://docs.perl6.org/language/rb-nutshell (to read how someone familiar with Ruby explains how to map Ruby knowledge on to Perl 6).
So why do it? Mainly, if the framework I'm currently using can't do things I need to do, or if it's incredibly painful to use. To the extent that someone has neither of those problems, a new language is a cure worse than the disease, whatever its benefits.
Look at it this way... imagine there's a rib joint across the street. It may not have the best bbq, but it's there. Do I walk across the street for bbq, or do I drive halfway across town to get slightly better? I'll take what's there, thank you. Now, if I'm a vegan, I'll get up and go somewhere else.