Using Docker / containers makes sense only if you need to standardize deployment pipelines. Otherwise it’s a waste of time.
When do you need to standardize anything? When you're dealing with a a large quantity.
So, either you:
- Have many (as in, double digits) microservices comprising one system, or
- Are in a very large organization with many development teams.
So if you have one or two apps running on Heroku / Beanstalk — leave them there. You’re not missing out on anything. It's pure overhead.