Square Enix is running out of ideas for raids

[Komarimono]

Then why are they not included in any of the roulettes, despite being very important for the oh so great story?

Even the devs know better than to inflict upon us the suffering of doing coils with casuals.

Wait, so because you've obviously not completed them and unlocked the savage, ya saying ya never once encountered Coils during normal raid roulette? Maybe fully complete it, and will show up in roulette for you. That's why you're not seeing it.