Its a good question. There is actually a difference in Credential asset and a normal asset in orchestrator.
Though this is also considered as an Asset in orchestrator, the way we process this is quite different. Compared with other asset types (text, integer, bool etc), credential type has two types. One is the username which can be considered as a string and the password which is an encrypted secure string type. Basically, it contains two values while others have only one. Additonally, Handling credential type is bit different because of this. When it comes to studio, Credential types are handled using Get Credential activity while others are handled using Get Asset & Set Asset activities. So, when getting values, usual integer or string values can be just extracted and used. But, the structure of the Credential asset is different.
That is why we need to mention the Credential type asset in the Settings sheet of the config, while others can be listed in the Assets page. Credential type asset is actually a setting more than an asset because usernames and passwords can be changed quite frequently.
Hope this helps!!
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