If your app depends on a few 3rd party services -- SendGrid, Twilio, Okta and they're all hosted on different infra then congrats! You're gonna have issues when any one of them are down, yayyy.
Also the marketing benefit can't be downplayed. If your postmortem is "AWS was having issues" then your execs and customers just accept that as the cost of doing business because there's a built-in assumption that AWS, Azure, GCP are world class and any in-house team couldn't do it better.