To answer in your tone: You misspelled distraction. ;)

...but seriously, it does not add any value to the presentation. Also, every photo has a caption, which can be truly a distraction. I can imagine if someone tries to read all of them and loses track in the presentation in every single slide. The author could have decorated with something on-topic, if he felt the slides were too plain.

I like photos as decoration, but they all have captures, in the same font as the presentation. The captures have quite some information (like the heights of the mountains). The photos are placed where you'd expect presentation images to be as well. But it's all entirely unrelated to the presentation.

All in all it's much more distracting than normal decoration.