Despite availability this feature still needs improvement to be considered as an alternative for this in Skype, Teams, Slack, Zoom... Recent update (about video stickers) in particular claimed that quality of screencast has been improved, but it doesn't really seem so. The resolution is still very low at least.
Hey guys, its so good they added this! Now just one more important change and Telegram will be unstoppable. Upvote this feature up!