According to Google, GTM is easy, simple, and reliable. Also, Google claims that every person can use it without needing a web developer. However, every person should be prepared to learn about the program and acquire additional information. GTM users need technical knowledge to understand how to set up the tag, variables, and triggers.
There are many layers to GTM, which is why it is a program that people will need to invest some time into if they want to use it. With the many different functionalities of Google Tag Management, GTM users need to learn not just GTM but parts of Facebook pixels, event tracking, and more.
However, this does not mean that the learning curve is steep. People will find that once they have gotten over the initial hump, it is pretty much smooth sailing from here on out.