so you honestly think after you hit 182 gs challenging modes are not as important as DZ?
After 182, vanilla challenge modes will drop 191 gear set gloves rarely, and have a rare chance to drop a 204 weapon or gear piece, but aside from 32 pxc per completion (30 pxc challenge mode completion award + 2-3 pxc for downing the named elite at the end of the run) and some standard currency, that's it.
Farming named elites in the DZ grants you DZ currency, DZ rank, at least an HE piece drop per kill (disassemble for HE materials, or possibility of a better piece in general), 2-5 pxc per kill, division tech, and a rare chance to drop gear set pieces or 204 weapons (same odds as boss kills in vanilla challenge modes). DZ currency and rank is required to purchase blueprints that craft at 204 using division tech (as well as upgraded versions of b.o.o. special vendor blueprints, such as improved gear mods), which in turn gives you a means to perfect your build later on.
Incursion runs on hard grant you a guaranteed gear set piece (191-214), along with pxc, standard currency, an HE drop, and the possibility of rare apparel/weapon skins. Challenge mode ups the gear score of rewards to 240, and increases currency reward as well.
You can spend 10-15 minutes farming a vanilla challenge mode quickly, only to see one drop that likely won't help you and 32 or 33 pxc, or you can spend the same 10-15 minutes downing 2-4 named elites in the DZ, giving you 2-4 times better odds to see a helpful piece, as well as building your supply of end game materials/currency.
I won't say vanilla challenge mode runs are worthless past 182, but they sure do give a lot less than you can be earning otherwise. If all you require is pxc, run em to death.