The bot has access to any sent messages to yourself, plus any chatter in group chats if you have enabled that. So don't use it for sensitive stuff, and use a dedicated group. It was developed to relay sensor data and such, not war plans.
Now, I do not plan wars with Yemen but still want to keep my private conversations with my wife about my furniture, well... private. For solving notifications I can just do what I do now: selfhost matrix and apprise.
So the whole solution seems interesting, though I fail to see point of using it whatsoever.
If you could self host it yourself too? Yes but like that? No.