Websites with user input should definitely use HTTPS. Since 2014, Google uses HTTPS as a ranking signal. Therefore, even with static websites like the one from my uncle, a migration pays off. We took advantage of the situation to also switch to a more meaningful domain, and with the help of World4You, this was done in two days. After that, I was able to get the full old website http://ernst-reichel.at running with HTTPS on https://autospengler-ernst-reichel.at. Now, users are calmed down because Browsers display the site as secure, and nobody can spy on the customers looking for spare parts or repairs. Each legacy site can be migrated!