This is evasive and dismissive. When your parent is talking about the issue, there's a good chance he is already using it. Telling him what "the real world" does is irrelevant. He has a use case already, and needs a solution for his use case, not for the rest of the world.
1. Many, many people used it, and continue to do so.
2. The anti GnuPG crowd keeps coming and touting alternatives, and then complain when the people in the prior bullet point out the impracticality of the alternatives for their use case.
We get that GnuPG has issues. We get that sometimes the alternatives are better. We can coexist with them. People simply don't understand that for a number of tasks, GnuPG is totally appropriate, and solves the problem with little pain.
In your real world, probably. In actual real world, people use MS Word/Excel (or LibreOffice) and images a lot, beside PDF. Good luck using e-signatures with that :)