Also, on the contrary, these platforms are used to eliminate a majority of "unpromising" candidates. It's just the easy way out for recruiters - outsourcing filtering mechanisms.
As such the hiring problem is multi-layered. Programming is just one aspect of software engineering. Well designed software requires wearing multiple hats and requires thinking which novice programmers lack.
When you make hiring a sport, you are likely to find more gamers of the platform than real problem solvers.
Just read the comments on this article for the general feeling amongst experienced developers : https://dev.to/raddevon/hackerrank-is-teaching-you-to-write-...