Hi @miczat
The transformer Creator was used on this context to Start / begin the reading process in the transformer FeatureReader.
One of the benefits of the FeatureReader as opposed to regular readers is that it's possible to make it dynamic based on the initiator feature. E.g. you can use it to read only features from your dataset that fall within your initiator feature.
In this particular case the Creator doesn't offer an additional benefit, but you could for example have it create a feature based on user parameters and then use that feature to extract a subset from the data in Geopackage using the FeatureReader.
In addition to the other responses, it could be that the workspace uses the Schema output feature somewhere downstream. The schema feature is not available from the regular readers.
I also find it easier to set the execution orders of multiple Creators, rather than a mix of Creators and regular readers. This gets to be important if you need to optimize the workspace by "unblocking" transformers, meaning that you have to make sure that the data flows through your workspace in a specific order, e.g. when using the "Suppliers first" option of the FeatureMerger.
Granted, both of these reasons are fairly advanced usage.
@danilo_fme , @Hans van der Maarel and @david_r - thank you all for your explanations, its appreciated.