There's some info from Medium on the topic:

Medium’s algorithm uses the number of claps as a signal to assess the quality of the story you read in relative terms:

“When ranking stories, our system will evaluate claps users give out on an individual basis, assessing their applause for a particular post relative to the number of claps they typically give.” — Medium help

and there's my silly opinion :D

https://medium.com/all-about-m/how-50-clappers-are-screwing-over-writers-4914327ef538