This same argument is made over and over in many threds. I don't understand why this is so hard to understand. Even mobiles and social media were totally new to the older generation but they got used to it. How is this any different ?
Using mobiles/social media is a lot easier to grasp than the steps under "How to do it". Copying files around a mobile file system and building a whole Android application is completely different to what you are talking about.
I think he's talking specifically about this migration tool, not generally about using Signal as a chat app