In general, System Security level affects :
- Pirate drone (rats) spawns in Asteroid belts : The lower the security level, the more chance that harder rats will spawn in the belts with higher bounty payouts to match.
- Ores in Asteroid Belts : The lower the security level, the higher the chance of better quality ores in the belts, although note that while rats can spawn at any time throughout the day, ores only spawn during the server downtime.
- Exploration : The lower the security level, the more chance that better quality sites will be found, with better quality loot to match. For the combat type of sites (anomalies, and DED sites), harder rats will spawn in them. For the hacking types of sites (Data and Relic sites), the Hacking minigame will be harder.
- Mission Reward and Loyalty Point payouts : You get better payouts the lower the system security level. I'm pretty sure this is based off of the destination of the mission rather than the location of the agent. There are many other things that can alter the payout though, such as certain skills, how long the game thinks the mission will take, and others.
- Concord retaliation and response Times : Being at or above 0.5 means Concord have rules about what you can and can't do to other ships/players/structures. The rules stay the same no matter what the exact sec level above 0.5, however the higher the security level, the quicker that Concord will warp to the offender and blow the ship up.