During my master's studies, so far, I have taken quite many postgraduate-level courses (i.e. courses that are accepted as a PhD-level course for a PhD student at my university). Some of these courses were a part of my degree requirement, so I was obliged to take them, but few of them were my personal choices to take them. I am now wondering if this can be a positive point in the future in my CV, e.g. when looking for a job. In the transcript of records, it is not indicated anyhow that those particular courses were postgraduate level, except for a "P" in front of their names and that's about it, so even if I send my transcript to someone they probably won't realize those courses are PhD level courses. So was it really worth the trouble to take such courses which mostly took me twice as much time to complete? I am not talking about things I have learned from these courses, but merely talking about their benefit in the future when applying for a job or PhD program?
There are actually several benefits.
You don't need to wait for people to understand what those "P"s mean. You could just add a section to your CV named Highlighted Courses and indicate the grad courses explicitly.
If you are going to pursue a PhD, the message that "I have already took courses from PhD and I know what I am doing" is really a good message to give. It will put you one or two steps further.
Completing a higher level course (i.e. post-doc course in master's) mean you are a hard-worker and ready to take the challenges. This message might come in handy when you are applying for industry positions.
They indicate that you want to learn new things. You are not a person that sticks with the "maximum benefit with minimum effort" principle. You actually want to expand your borders. This indication puts you four steps further both in academia and industry.