Earlier quoted context omitted.
You install Telegram, you contact the bot https://t.me/scihubbot , you send him a DOI and it will answer with the PDF (if it has it). Sometimes it says (in Russian) there is an error fetching the paper: I understand that in such a case it does not have the paper, but the paper is available on GenLib, so you can go there. But it is not frequent.
That sounds as if it's adding another layer (and possible failure mode) between you and Sci-Hub. How does the bot itself access the content? What keeps it from being attacked as Sci-Hub has, by publishers?
SciHub is unfortunately rather opaque on its internals (and that is definitely something that I would like to see changed), but it seems that the Telegram bot is blessed by the official Twitter account. In practice, I have often found it more reliable than the website, and it does not have problems with finding the right TLD. Also, as I said, it retains the history and it shared is with other devices, provided that you consider that a plus.