Is it worth joining upwork site for earning?

All I can say is do some research.

i am not familiar with those site. i tried the swagbucks but it's not about writing.and i am not active on that site too. you need to make more research and good review regarding of the site you are going to join

I haven't tried this site. Perhaps you can try Virily

I know that some users write for textbroker and they are well paid for good articles, I do not know the other sites.

Upwork offers you to bid on different jobs according to your won preference, If a client accepts you then you get the writing job from them and write what they want you to write, It takes a while to get a job though, I have worked with several clients there and enjoyed it. You can also try Guru where you also get to bid for jobs and let them know what kind of writing you want to do. You can try Textbroker where if they accept you then you get online and take a looked at the assignment and chose the ones you want to write, Submit them and then wait to see if the client accepts your article. I have made some money with them, Another good thing is to get online and take a look at all the writing job sites available,

I was a member back then and I did small tasks such as data entry as my only skill. But, they suspend my account indefinitely for the reason that I was not able to land for a job after multiple applications. If you think you are skilled enough, you can join the pool of individuals there and get a job. Good luck.

I don't work for any of them so no idea.

Pico paid me