Is There a Scarcity Effect?

I've been critical of this strategy in the past. And partly that's just because I saw a lot of people using it all at once. Why in your view have people reply if you could just post the link straight to the beehive page inside the tweet? Is it that the reply builds like an extra layer of commitment or why have the reply at all? So like this sort of goes to like my marketing psychology stuff. Like when people think it's like scarce, they want to go more for it. But when you do the tweet giveaway, it's like one scarcity to like momentum racks up,. When you put the link, people just click the link and then their audience sees