It did not cross your mind that the payout amount could be less than what people expected ? This extra step is a simple precaution to make sure people will let us know that they are in such situation (in those rare cases, they will then be requested to show a cryptographic proof).
Now you are writing that clicking on a button is such a difficult task that you can suggest we did it "to gain money"?
Pathetic.
"It didn't cross your mind" that paying out without requiring to click a button would also be a nice gesture? So if the wrong person got the link, he will press the button no matter what. If the right person receives a smaller amount than expected, he will complain no matter what. Clicking the button would have no legal implication if later it occurred to me that you only sent me half of my money as the amount is kind of hidden below, so why bother thousands of users with this extra step? I assume that clicking this button costs on average 2 minutes taking into account all the people that regularly checked their wallet to see if their claimed money arrived (in my case with my Iraninan friend it cost 2 hours and involved 3 people) so the justification to having this button in the first place are pretty lousy compared to 10.000 * 2minutes = 13 days of your users' time.