"... I never understood what Azure actually is. All I hear is some buzzwords."
A common problem in the software world, not limited to MS.
The question is whether this is intentional or whether the company lacks the ability to actually tell you. Communication with the customer might be handled solely by marketing executives who may not understand what Azure actually is. The code might be so needlessly complicated that even few developers have a wholistic understanding of it.
One of the great things about open source is that if the need arises the customer can find out what something actually is. The system can be disassembled into smaller parts for a better understanding. The source code for individual programs can be read. The code for the compiler is also open for inspection. This has great benefits.