Because relatively high-level PvE content (Epic Arcs, Drifter Holes) should in general provide useful rewards.
I have no experience with drifter holes, but regarding the Caldari Epic arc:
It probably provides the most valuable faction standings out of the four L4 Epic Arcs, it’s physical rewards are lackluster. You either get a Blueprint that once produced brings a profit of ~100M ISK but required Outpost Construction skilled, a bunch of boosters that nobody needs or 25 million in cash.
Meanwhile the Amarr Epic Arcs provides either a 260M implant (highsec path) or a 600M implant (lowsec path), the Gallente Epic Arc makes you choose between two 300M implants and the Minmatar Epic Arc gives you ~200M worth of Scan Probes or 25M in cash.