Can a thunderbolt 3 cable be used on MacBook 12inch for data transfer? I just got a new 13-inch MacBook Pro  with Touchbar and I need to transfer my data from my old MacBook 12 to it. While using migration assistant over wifi, it always has errors or got stuck so I'm going to try the target disk mode. I did some research and a YouTube video says I need to use Thunderbolt 3 cable, so I just went to a local hardware store to buy the cable.

However, the stuff there told me a Thunderbolt 3 cable will have adaptability issue on my 12inch MacBook and recommend me buying a 5Gbps USB-C cable. Thinking I might use thunderbolt 3 in the future and their price difference is not that large, I will definitely choose a thunderbolt cable if it can be used. Speed is not an issue.
I am answering my own question. Short answer: NO.

I received my Belkin Thunderbolt 3 cable today (https://www.amazon.com/Belkin-USB-IF-Certified-Thunderbolt-Compatible/dp/B0725DW6D3/ref=sr_1_4?ie=UTF8&amp;qid=1511766135&amp;sr=8-4&amp;keywords=belkin%2Bthunderbolt%2B3&amp;th=1 the 1.6 foot one). By directly connecting my new MacBook Pro and MacBook 12inch, the new MacBook Pro still couldn’t recognize that 12inch MacBook. I did some more research just now, and on this page(https://support.apple.com/en-us/HT201462 scroll down to the bottom), it seems that a USB-C 3.1 cable is the only way that does the work. The shop assistant was right.

I am not sure if it could work with other situations, but unfortunately it doesn’t work with target disk mode. Btw, the cable doesn’t have any problem since my 12inch MacBook was charging when connecting to the new MacBook Pro.