The bad news: Summoning an entire elder god is hard. They end up summoning one of the innumerable lesser horrors in the elder god's orbit.
The good news: The summoned entity is going to grant them immortality.
The bad news: The players will experience an eternity of never-ending horror and torment.
The good news: Since it's just a (relatively) lesser entity, the players actually have a slim chance of ending this curse, returning to blissful mortality.
On the same note, the target audience is mostly white dudes. It's a lot easier to sell them the fantasy of playing as / fighting against Thor, Zeus, or Hercules than it is to get them excited about some character they've never heard of and can't even pronounce the name.