Delves are the solo-friendly gear track, and they are also the most repetitive one. Bountiful Delve runs, tier unlocks so you can go straight to the level that rewards you, Restored Coffer Keys so every run actually pays, and the achievement chains — all of it on one page.
Delve work is quick to start and cheap relative to raid or Mythic+ gear, which makes it the fastest route to a usable item level early in a season.
Why unlock delve tiers first?
Reward tiers gate the item level you can get, and grinding them yourself is the slow part. Unlocking the tier first means every later run drops gear worth keeping instead of vendor trash.