The stupid stuff is all important to someone. The stickers on telegram are the main reason furries use the platform over discord for example.
And mobile platforms auto update now so while it’s possible there could be an old version out, not much effort is put in to making it work. Telegram shows a basic text showing the message is not supported on your version and prompts you to update.
Even the stuff that is hardly a feature but more a UX prompt is important. Discord voice channels are not that much functionally different to traditional group calls, but that way they get used is dramatically different because the UX is.
Imagine if someone bridged discord to some other IM app and when someone joins a voice channel, it starts a group call on the other app which opens a ringer on that persons phone. The compatibility is close enough right, but that minor difference is enough to make users very upset.