You'll unlock the Hero Slayer Badge, Villain Disruptor Badge to access the contacts for Mayhem and Safeguard missions. (I do it for my villains at or before 45 because the Invader badge is easier to unlock the powered accolade.)
What I'm proposing is more then unlocking the Invader Accolade. I'm proposing a flashback that is another backdoor to the Invader and Safeguard Badges, a new revenue path for merits, a reason to select Join In Progress in the LFG system (if it even works), a PvP/Arena option, and a new Homecoming powered accolade that has a two stage boost for the Status Effect: Fear by collecting all the Mayhem and, or Safeguard badges. Almost every team is running radio, paper missions (mainly radio) but ignoring bank jobs even thought bank jobs give great rewards: Resuscitation (Self Resurrect); Summon Teammates; movement, endurance, health and regeneration boosts.... They could just modify the bank job rewards to include merits and add the Homecoming Accolade via the Lord Schweinzer and Agent Hassell as they are technically Flashbacks. And if they did decide to do this, then in the following issues, more Homecoming powered accolades for other status, mez, effects like immobilize, taunt..., and then onto boost like 5% psionic damage (3% for unlocking the Hero/Villain then 5% for unlocking both) link to existing (echo) badges, plaques and defeats. I already "cheat" to unlock the Marshall Badge by unlocking the The Atlas Medallion Badge as few run the LRSF.