There are so many blueprints that send notifications. To do this the authors typically have to rely on this odd workaround. Where instead of asking for a notification service they ask for a mobile device. That way they can create the notification for users using all the data available in the automation (which often involves complex templates you wouldn’t want to ask blueprint users to write).
But inevitably one of the first feature requests is to support notify groups or telegram or one of the many many other notification options available in HA that isn’t the mobile app. If you want to attempt this as a blueprint author the best you can do is add a text selector and ask them to copy and paste the id of the service. And then you either have to assume the only safe field to use in the service call is message or try to tell people what notify services can and can and cant be used if you want to set title, data, etc
It’s all very error prone. And it’s frustrating because the user expects it to be simple. It would be great if there was at least a notification service selector to eliminate the copy and paste part. Even better would be some kind of supported_features option for notification services so the blueprint author could say what features are needed and the user would only be prompted for notification services that worked in that spot.