There's a good chance if you're applying you're either a. unemployed, looking for a job, or b. you really want to work at stripe.
If you're passionate about what you do, you're going to enjoy designing anyways, so what better way to make you stand out than doing something that benefits the company you're applying for -- working on something you'd actually be working on.
Anyone can copy designs from dribbble to make themselves look like an amazing designer.
It's not like they're going to take your design, implement it and never reply to your email.
I do not mean this as snark. And I certainly would be open to the idea of a trial period or working on an in house project after the interview. But to ask someone to put in hours just for the possibility of an interview seems like a very asymmetric request. Am I off base here?
EDIT: It's probably worth noting that I work more on the software side than the design side.
a) I've found that lots of design applicants will put stuff in their portfolio that they contributed to, rather than built end-to-end. This solves that problem.
b) Tracking on the statement above, they're looking for a designer that has a "deep understanding of how applications should work". In an online design portfolio it's easy to misinterpret application design skills w/the ability to take a design spec from a product manager and make it pretty. Stripe is looking for a unicorn - a designer that is also a product manager / UX talent.
c) Design, especially UX design, is not just a "show me your portfolio" - it's a "what is your process to build the right UX." If a candidate submitted several iterations of design + maybe a "let's test these two things because I'm not sure" I would be 100% more likely to prioritize their app vs a "look at how pretty this is"
So I don't know, I get the argument that this is taking advantage.
But on the other end it makes them a lot more likely to find an awesome candidate who actually wants to work there, and has the talent to deliver the goods.
Effective designers (and effective hiring managers) have already solved this problem by describing their role in projects (or asking about specific roles in the interview process). Don't hire designers that have a portfolio full of nothing but sex-shots.
> "what is your process to build the right UX."
I agree that is the intention of this sort of application requirement, but I'd be surprised if it consistently worked. These sorts of requirements force designers to work in a vacuum. It is impossible to make an effective solution without having a deep understanding of the product—the hiring company will get a tepid/run of the mill/boring design. (Though perhaps a beautiful design, which often works for these sorts of interviews)
> But on the other end it makes them a lot more likely to find an awesome candidate who actually wants to work there, and has the talent to deliver the goods.
It's maybe likely to find them someone that wants to work with them (especially if we define "wants to work here" as "willing to do spec work" which may be fair) but in my experience, talented designers are busy working on cool projects and students/young designers are the ones with time to dedicate to this sort of application.
A better way would be to go through the normal filtering process of accepting applications. Choose several designers, then offer them this same task with proper payment for their time.
If the concern is whether they can strike the same tone and style, hiring people on a temp contract is usually a better way to go, plus then you also test if they're fast, present their work with a strong rationale, play nicely with others, etc.