Most people use Telegram for its superior set of features and convenience. The fact that everything is stored on the server-side actually works in favour of its user base by giving them a functionality many desperately need - that of accessing all chats and records ubiquitously, from wherever you want, at any time, from any device. The ability to make channels and groups of thousands of people only works into making it a pseudo-social-media super-app that appeals even more to its users. Besides, it allows you to remain anonymous on its platform despite requiring a phone number for registration.

I have seen so many people going through the horror of losing everything on WhatsApp whenever they switch phone platforms - the chat backups it creates are not transferable across Android and iOS for some reason and there is no way to recover your conversations at all in such a case. Telegram covers many things where its alternatives fall short, but privacy and security are not one of them.