They say it shouldn't be legal. The first answer on the FAQ:

"Whats happening?

Cards Against Humanity is exploiting a legal loophole to pay America’s blue-leaning non-voters to (1) apologize for not voting last time, (2) walk us through a step-by-step plan of how they’d vote this time, and (3) post “Donald Trump is a human toilet” on social media. This whole thing should probably be illegal—so quick, give us your money before they change the law!"

The entire FAQ is worth a read, it's pretty funny

It's not asking for either of those things. The site's terms explain it pretty plainly:

We are running a promotion to encourage eligible voters in the November 5, 2024 General Election in the United States that were eligible but did not vote in the 2022 or 2020 general elections to apologize for not voting (the “Promotion”).

[...]

ii. Receive an Entry by completing the following process:

1. Entering your phone number;
2. Entering your name, state of residence, and email, or additional information if needed to verify whether you voted in the 2020 General Election;
3. If you did not vote in the 2020 General Election, enter your apology for not voting;
4. Create a voting plan for if you would vote this year;
5. To receive the full benefit, post on social media that #DonaldTrumpIsAHumanToilet. Not posting on social media will result in a reduced Benefit.

iii. “Voting plan” refers to your receipt of and acknowledgment of information on how you could legally cast your ballot in the November 2024 General Election.

iv. We will not check, confirm, or in any way ensure that you actually vote or follow the voting plan that you made. Creating a voting plan is not in any way a pledge that you will actually vote, and the Benefit is in no way conditioned on voting, or pledging or promising to vote. VOTING, OR NOT VOTING, IN NO WAY IMPACTS ELIGIBILITY FOR THE BENEFIT, OR THE AMOUNT OF THE BENEFIT.

edit: formatting

I agree. But it is a great example of why this is a shit idea that shouldn't be allowed in the first place which I wager is at least partly what they're going for

Pretty sure it's in reaction to Elon promising people who vote 47 dollars. You know, actually advertising to buy actual votes

Well, the other side is doing it so they're doing it almost identically so if they get in trouble for it, Musk should too.

Apparently it’s in response to Musk and Trump handing out money.

they are not paying people to vote, they are paying people to apologize for not voting.