It was a reasonable messaging app for a lot of folks in ~2013-2016. The stickers support was excellent and it had a lot of excellent features, even though its psuedo-open source stance was always a little weird. I also ascribed some level of trust to Pavel Durov as ultimately being anti-authoritarian given his history with Putin and thought that was ... fine, I guess. Anyways, with the rise of crypto came a lot of other unsavory things where Telegram became the de facto comms platform for criminals. While criminals will use any medium, it's also a matter of critical mass to me.