Nifi: Using parameters

Hello,

I have a question regarding the concept of parameter context.

The admin guide says : A Process Group can only be assigned one Parameter Context, while a given Parameter Context can be assigned to multiple Process Groups.

OK, let's assume you have internal kafka or database, and some external system you connect to. You might want to have a parameter "group"
for the internal kafka connection, and another parameter contexts for each external system connection.

However, your flow, clearly a part a process group, reads data from external system and stores data internally. Thus you need actually 2 connections in the flow,
it means 2 parameter contexts, which is not possible. To solve that, you assign the connections (controller services) to the parent group and the parameters.

Finally, for connections which are common to many flows, like your kafka, databases, and HttpSSL you land in the parent NiFi Flow, having parameter context which contains
a bunch of pretty unrelated parameters (for kafka, databases, ..).

What is see, there is hardly a possibility to reuse parameter context
as they cannot be combined and thus you have 1:1 relationship between par. context and group just like for variables assigned to a processor group.

Did I miss something? What is actually the big advantage of parameters over variables?

Best regards
Jaro