He's probably adding those random videos to a playlist because they're the ones which earn them the most money.
Some people were saying before that a definitive x number of views = x amount of money. That's not true. A vlog could get 25,000 views and earn the same amount of money as a vlog with 750,000 views uploaded by the same person.
If you search other videos on youtube of people explaining how youtube pays them then you'll see that money earned per video depends on how successful they are for people clicking on the ads during the videos, how attractive the video content is to advertisers, how long the video is and retention rate (how long people stay on the video before clicking off it) and how few people use adblockers during them, plus the ages of the people watching them.
A viewing audience with people aged 18-35 (the generation with the biggest spending power) will earn a youtuber significantly more money than someone with child viewers...and that goes PER VIDEO, not per channel.
Creepy has access to all this data and deliberately targets this audience and tries to repeat the same content which has earned them the most money in the past (not determined by views-per-video). I'm guessing that's why stupid challenges, SURPRISE! titles, kids with those awful pweirdo-lite open-mouthed facial expressions and crying faces are repeated over and over again despite the frequent criticisms and low view counts they get for them.
This person explains well how she's paid, what she gets and the financial differences between videos/views, she shows her account details too (it's only 10mins long)