I think OP missed some grammar

Yeah, I think this is what the OP means. Funny thing, almost all of the comments in this thread are making fun of this mistake, but not many people are answering to the question the OP asked... :I

Indeed, but there is only a comma missing though in my opinion, it would read much better that way:
"Is it basically a platform for steam users to give away games they bought, for free?"

True that, I didn't get that at the moment :)

It tickles.

SO MUCH!!!

because there could be more than one $50 giveaway

Yeah, if you want a game really bad, you shouldn't trust on this site to get it. The chances to win are usually pretty small, especially on public giveaways. This site is dedicated mostly to the joy of giving, not getting. At least that is what it should be.

And I'd like to point out many people buy games from sales and give them here. You see, you get the contributor value based on the Steam Store normal price, it doesn't matter if you had bought the game on discount. You could easily obtain $50 contributor value by spending less than that, even just $10 for example, by taking advantage of good sales.

The "advantage" is that once you have, as given example, a $50 contributor value you can now enter every contributor-only giveaway with a gateway value of $50 or lower, which will have slightly higher winning odds by simple merit of disallowing those without said value (me, for example).

Beyond that, the answer to "why" can be as simple as "why not". Perhaps you want Multiwinia but don't see it as a $10 value. Maybe you're broke and want a chance to play something new? Maybe entering giveaways gives you a chance to win a game and save that $50 for booze or a hooker? Or you could be a cheapskate looking to score some free games. The point being: Why not? And then down the line, if you've gotten a few wins and feel like giving back, well, there's your reason for that $50. Me, I gave a couple things away on my first day before having won anything and even before knowing contributor value existed. Sure, they were cheap and/or bundle items, but I had no use for them, so why not? :)

The point is not to get what you want, you can buy that. The point is that it feels good to win something, and you can enter for things you're not convinced enough you'll enjoy to buy. Some will be disappointments, others will be wonderful surprises, but the varied experience will probably make you a better gamer.

Wait until you hit 1 year ;)

In time, my child.

In time.

Who said anything about minigames?