If you have some background or experience on some of their tools, taking the whole learning path would be fairly quick I presume.

But for someone who wants to dive into GCP, the learning path has the estimated time. In addition, although not necessary, you can try to explore the GCP to get a good grasp on their core services.
Trying to match the course learnings with the actual service. This will take several days, more than a week.

I had some familiarity with some of the core services which helped me focus on my weak parts of the learning course.
This translated to a bit of confidence in taking the exam which made it look easy.
But the passing rate is higher which I estimated that if I fail on my weak points, would make me fail the exam.