I have just tried many time to run the command without providing login id & password because I thought in such case the current credential will be used (as you mentioned) to schedule the task.

I found it is scheduling the task and in the GUI you can see that the task scheduled under the current credential but at the specific time the task will not be executed. I am getting error message
[TRACE] Setting account information
[TRACE] Setting job's properties
[TRACE] Created trigger 0
[TRACE] Adding job 'Aramco2K.job'
[FAIL ] ITaskScheduler::AddWorkItemn hr=0x80041310