Indeed, it is intended to be flexible and reusable for all kinds of calls, similar to what is possible with the postman UI. If you have any suggestions, let me know. We are currently improving this component on a weekly basis.
Using dynamic URL parameters and/or dynamic bodies can be challenging when you use it for the first time. I am happy to write more detailed instructions on that if you want 
Also see: Call Templates - Using call parameters in a call template export - #2 by j.batzke