I know that if I follow a question, I am notified if the question receives an answer. I am also notified for every single comment, edit, close, etc.
I see some users who are actually good contributors. Most of the time, they provide answers to valuable questions. Also, they generally do not ask questions.
For example, as I think user (M.x) is a good contributor on Stack Overflow, I want to be notified of all his answers, give us the ability to follow specific users' answers.
I don't know about the possibility to implement that feature or about the complexity.
For study purpose, would it be helpful?
Personal Opinion: I think it will be helpful for me.
I know there is a way for everyone to see all questions/answers and also without logging in. Also, I know If I go to one user's profile and vote on his questions/answers, that's serial voting and will be reversed and both accounts can be banned. Also, anyone can say that you can bookmark the user's profile and check their answers every day.
But notification is different. It will remind the user that you have something new you can read/learn now. If anyone thinks this way, it will be helpful.