After playing around I found several reason for the two commands.
1st example:
// thread //go person joyrana
This makes sense if shyrana stays far away from the bot shyrana because otherwise any further entry in the chat by shyrana will stop her from walking.
2nd example:
//go 5 n
// pause 15
//go 5 s
[17:11] Going North to 23,202,2255
[17:11] pausing for 15
[17:11] Finished walking 0 meters from destination
[17:11] shyrana: how are you
[17:11] joyrana: fine
[17:11] paused for 15
[17:11] Going South to 24,192,2255
[17:11] Finished walking 0 meters from destination
In the example I ordered the bot (shyrana) to walk 5 m to the north, wait 15 seconds and then walk back. The commands got somehow queued. during the pause shyrana talked to joyrana before she went back using the queued //go 5 s command.
In some situations a combination of the two commands (thread and pause) might be useful and even necessary.
Maybe there are better examples. Please provide them if you have some. I did this here due to the lack of documentation.