Cannot see my HIT created from the API using boto3 and Python

I am planning to do a large scale crowdsourcing experiment with approx. 1000 HITs and 3-5 assignments each. I would like to do this using the API and Python, since I am very interested in the ReviewPolicies Feature. I tested this (not only in the sandbox, but also in the marketplace) and can't find my created test HIT (reward set to 0.01).

What could be the reason for this? Also I read in external forums, that HITs created with the API are not visible in the developer interface. But they must be visible to workers on the website interface, aren't they? If not, how will these HITs be found.