Are these guys on twitter legit?

So I see a lot of people doing this where they want you to follow, retweet, like and then show proof for a chance to win some specific amount of Crypto.

I see this quite often now, just wondering are these guys legit, cause I never see them announcing any winners, they just seem to repeat and repeat contests.

Is this some sneaky way to get followers or something? Has anyone won anything from those fellas?