The chance to practice the harder raids is terrific. I learn best by doing, and it gives me a great chance to get better at mechanics and learn the finer points of these harder fights.
Or at least, it would, if I could ever find a group to do them. I very occasionally see Rehearsal runs up, though they’re usually not starting from G1. But I’ve never seen a Deja Vu run up. The only one I’ve even gotten to be part of required a lot of public advertising, and a wait of over half an hour to even get mostly full, not even completely full.
A likely culprit is not allowing people to both practice and do the real thing, because the rarity of learning parties is increased when it stops you applying that education that week. I want this to work, I want to learn the fight, but I’m not given the chance to.