From my perspective, the fundamental justification for sortition is that randomly selected citizens are more representative of the general public and, crucially, less corrupt and corruptible on average than elected representatives.
Why less corrupt? Because I think people who seek power are more corrupt and self-centered on average than those who have power thrust upon them. Why less corruptible? Because randomly selected citizens don't have to fundraise for political campaigns, and they are merely temporary occupants of their seats, not running for reelection and becoming career politicians. As far as I'm concerned, political campaign contributions are legalized bribery. It would be easier to police citizen legislator corruption, because we allow crap from elected officials—campaign contributions, gifted travel, post-legislator lobbying jobs—that we really should make totally illegally and jailable. A lot of "working class" politicians suddenly become super-wealthy after leaving office, and we all know it's quid pro quo. Just outright ban that crap and strictly audit former legislators.