These sites typically display a lot of ads and likely also has a lot of competition.
This means, the remote jobs listed aren't checked by humans and you might have to sift through a lot of unusable jobs. Secondly, you'll find some free sites below that list hundreds of different remote job postings purely via an RSS feed. If you want to dip your toes into freelance life, nothing wrong with using Upwork or Fiverr, I have too in the past, just know that these gig economy sites own the entire relationship with your clients and anyone can put up a job without any real filters build into it. They can even watch your screen on how you work, plus the introduction of their points-based system makes it hard to compete when you are brand new and just starting out as you'll be forced to compete on price. The main reason being that they take roughly 20% fees on everything you make while working via the platform.
I believe they are great to test the waters with freelancer work and independent clients, however, they are less than ideal when looking for a part or full-time remote job. It's likely you have heard of sites like Upwork, Freelancer and Fiverr when you read this.
