they’re challenging but they don’t give you anything so why do you want to challenge them
There is an ISK reward for killing the Pirate Base, but not the individual pirate ships. It usually takes a group to kill a FOB, or at the least a dual-boxer with a very good fit and skills.
Diamond rats exist to keep you on your toes and discourage AFK gameplay. It only takes 2 seconds to check The Agency to see if there is a Pirate FOB in or near your system.
And most AFK’ers are too lazy to even do that, so diamond rats end up killing quite a few ships…
Because you mentioned rewards … if you want to make better ISK with less skillpoints, don’t kill NPCs in higshec. There are better methods to make much more ISK, much less boring. Exploration in wormholes / nullsec, ninja gas harvesting in wormholes, ninja looting gank sites or fight areas in lowsec. All activities which need minimal investment in skills and equipment, but require valuable player skill you can learn.
One of the goals in EvE (imo) is to find the least boring way to fund yourself. The obvious mechanics, because they are obvious, aren’t.
diamon rats with miners, have npc haulers regularly visiting them.
these haulers drop skin box (about 50% of the time). which is worth enough to go out of your way to hunt them (25mil+)
also gurista and blood raiders box dropped from haulers has small chance of faction mining drone blueprints, which is why its even more expensive (120-200mil depending on market activity)
for reference enter ‘strong box’ in market browse window