I created this alpha channel from a picture of me and my son that I liked. It was relatively easy to do as long as I followed the step by step directions.
The concept behind alpha channels is a little hard for me to grasp, but this link: https://www.webopedia.com/TERM/A/alpha_channel.html helped simplify them in my mind by calling them a pixel mask. I can think of a lot of uses for an alpha channel Tiff, including using it instead of a selection mask which is something I have already done. You could use them in memes too, the Meanwhile in Russia and Putin memes come to mind.