When you say Content Transfer, does this mean you want to move content from one environment(it can be either on-premise or AMS) to another environment (AEM Cloud Service)?
If that is the case, then yes you can use the Content Transfer Tool for it. The Tool was developed to move existing content over from a source AEM instance (it can be either on-premise or AMS) to the target AEM Cloud Service instance.
If the target instance is not on AEM as Cloud, then I think the Package Manager is the best option.
Also you will get more information from the below links:
Hope this helps!
Thank you Asutosh, i got that CTT is used to transfer the content from your on-prem or managed service environment to AEM as cloud service, but the objective is to transfer the content...so was curious has anyone use this tool if the is need to migrate everything in prod to lower environment.
Also Package manager is not recommended when the data is huge more than 100GB so maybe vltrcp or grabbit can be an option but not sure whether grabbit is supported for 6.5.6 version.