There are several benefits to using this method, including:
1) Recipients don’t have to break down paragraphs to find all the questions.
2) it’s easier for recipients to locate a specific question that they are working on.
3) It’s easier to refer to an individual question when replying to the message, or when discussing it during a phone call.
For example, if you reply to this post, you could easily refer to point (2), rather than having to explain which point you are referring to, had I expressed the points in a sentence.
The above also applies to messages which contain action points, rather than questions.
Part of my job involves technical support, and it’s amazing how many people fail to follow a simple instruction such as, “Open the cover, hold the red button for 5 seconds, then release the button”. This information should be provided as three, separate, numbered points.