Is downloading YouTube videos legal?

It seems to be allowed when there is download link.

As it is written in YouTube Terms of Service, “You shall not download any Content unless you see a “download” or similar link displayed by YouTube on the Service for that Content.You shall not copy, reproduce, make available online or electronically transmit, publish, adapt, distribute, transmit, broadcast, display, sell, license, or otherwise exploit any Content for any other purposes without the prior written consent of YouTube or the respective licensor of the Content. YouTube and its licensor reserve all rights not expressly granted in and to the Service and the Content.” But you can still use it for your personal use without distributing it someone.