An interesting contrast: for as long as I can remember (I've been at Amazon for 5 years) we've had burner AWS accounts available for testing/prototyping stuff that get auto-closed after a week. Many devs, myself included, also have a personal long-lived AWS account for infra stacks of the services we're working on. These accounts get billed directly to the team's fleet budget. As long as you're using them for work-related things (i.e. not mining crypto or hosting a minecraft server) and not racking up massive bills without a good reason then it's fine.