Please don't exclusively use Twitter for communicating important announcements
If you want to make use of Twitter to send messages of importance make sure you consider having other options to contact people as well.
A little while back I remember watching a video by Mark Felton that talked about councils deactivating older emergency warning systems in favour of solely using Twitter. At the time I couldn't help but feel this was an amazingly terrible decision since not everyone uses Twitter and internet connectivity might also be problematic in a disaster even if everyone who needed to get the message did use Twitter. If for example if your town is getting flooded you may not have internet access, a low tech solution can be a really important thing to have in these cases. I was reminded of this video recently when the internet connection went out temporarily and was thankful this outage wasn't due to some emergency that required my immediate action.
Let's assume for a moment that everyone has uninterrupted internet connectivity, this plan can only work if Twitter will always be available and have integrity. After the 2020 Twitter bitcoin attack you really need to consider other alternative options for sending critical messages.
If Twitter can resolve these security and integrity issues I think Twitter might remain a reasonable way to broadcast a message as one part of a number of channels of communication. But even if they do, I strongly urge people not to exclusively use Twitter for critical communications and announcements.