Using rel canonical on non-takes. What do you think?

Question

Google

What do you think about using rel canonical on not duplicates but just extra pages? I often see this on foreign sites and very rarely in Runet.
For example: service page; after registration, an additional page with certain information is issued. It is not a double, but you can put canonical on it on the previous one.
Or here: page of the downloadable program. The link to the download is another page with a choice of a specific version of the program or something like that. From this additional canonical page to the main description page.
I know that search engines recommend using rel canonical only for duplicates, but I often see a non-standard way, as I described above, on bold foreign sites. What is your opinion on such use?

Answer 1

According to the examples described above, these pages should not be in the index, because. they are not landing, and the canonical is fully justified.

Answer 2

Well, if it doesn't make sense, why do it?