Warlords of Draenor: Garrison mission rewards at a glance
Players who aren't in the beta often have a simple question about garrison followers and their associated missions: what is the point? There are few resources that explain their purpose and what benefit they provide. The list of rewards below is by no means comprehensive and should only be taken as examples of variety. They're some of the items I've personally earned while dispatching follower missions on the beta.
Archmage Vargoth's Spare Staff for your toybox from a rare level 90 mission
Relic of Rukhmar to increase reputation with Arakkoa Outcasts
Shimmering Gauntlets and other Shimmering equipment at level 90
Gleaming Ring and other rare-quality Gleaming equipment at level 90
Munificent Robes and other Munificent equipment at level 100
Apexis Crystals in lots of varying sizes, up to 1,000 from a rare level 100 mission
Follower missions also reward XP for your followers, items and equipment to increase the strength of your followers, and gold. Basic level 90 quests often award 50 gold, but it can often be much higher -- a level 100 rare quest, Blingtron's Secret Vault, gave me 500 gold. These missions are far from mandatory, but there's no reason not to do them. Assigning your followers to their respective tasks will only take a few minutes out of your day.