The difference is that you, as an applicant, want to be part of something someone else created and to use it to feed and clothe yourself.

Nobody is asking for free work. And I definitely would never hire someone that calls a four hour exercise that is part of an application process "an indication you don't value yourself highly." In fact, it would be a huge red flag and I'd throw that applicant'a resume into the trash can.

And they, as an employer, want you to trade some of your irreplaceable time on earth for some money and the chance to "be part of something".

If you can't see the symmetry in the situation it says something about your values, but it is not a compelling argument.

Lots of good vendors offer free trials or guarantees without it harming their reputation. In fact most customers object to shouldering all the risk.

Homework is an investment, with some delay and some risk to it.