I'll pick TFE because Nomad doesn't exist as a service.

Audit trails, authorization, authentication, sentry rules (don't allow devs to open a public port for example), centralized automation (plans executed in order), dedicated build agents.

That's a few reasons why we used TFE at Capital One.

Curious -- is “used” past-tense because you're no longer at Capital One, or because Capital One stopped using them?

The former!