'Charge This Phone' vs 'Charge Connected Device' When connecting my phone to my laptop, I have these two options

Charge this phone (Just charge this phone)
Charge connected device (Charge the connected device via USB)

I don't understand the difference between these two options.  However, if I try the second option, it fails with the error

Unable to use USB cable for Charge connected device

To the best of my knowledge, the ports I tried were USB3, so that nixed my guess as to what the problem was.  What is the difference between these two options and if the latter is better, how can I use it?
Charge this phone


It means that your phone will be charged from the laptop battery via USB.


  Charge connected device (Charge the connected device via USB)


It means to charge your laptop via USB from your phone. Most probably, your laptop (like that of many others), cannot be charged via USB, so if you choose that, it is giving an error. But the option still persists simply because your laptop runs on battery. Had you connected your phone to a PC, this option would not have come.