Hi @Susja - I'm not in the habit of trying to convince anyone to do anything, but Notebooks are useful for folks who like to create "runbooks" from their scripts. For example, perhaps there is a set of T-SQL commands that need to run in a specific order, and should have certain output, and a Notebook allows you to save the output (not an option for a T-SQL script) so that it can be viewed later. Folks in the data science space who run R and Python also find them useful (info here: https://video2.skills-academy.com/sql/machine-learning/install/sql-machine-learning-azure-data-studio).
The question is really, "What problem are you trying to solve?" Based on what you've described, you do not HAVE to use notebooks. But if you find that you like the formatting options, saving output, and don't want to switch between the query editor and terminal, they might be great for you.