i agree that it seems easier to simulate working conditions with a homework assignment. (it does add a lot of work for the company to do homework problems well, but let's leave that aside)
the downside is that the candidate has a limited amount of time to talk to you. they often have a full-time job going on top of the job hunt. secondly, are you really game to spend 0.5-2 days of unpaid work just for the chance of being invited to interview further?
Also mentioned in sibling comment, but I was thinking more from the perspective of a company trying to accurately gauge a candidate's caliber. From the side of an interviewee, it definitely isn't a clear win; the only case where I think a candidate would prefer this would if they tend not to perform well in interviews (which I don't think is necessarily a good indicator of whether or a not a candidate would perform well for a job).
An additional perspective I didn't think of until now is whether this type of recruitment process would be more beneficial to the industry as a whole. An argument could be made that we'd all be better off as a whole if interviews tended to more accurately assess candidates and candidates were able to get a more realistic sense of the type of work they'd be doing for a company.
Also it doesn't scale for the candidate. If you need 0.5-2 days of unpaid work for _each company_ and you're applying at 20 companies, you're spending more time applying for jobs than you would be working 10-40 hours of unpaid work just to get to the next step.
i agree that it seems easier to simulate working conditions with a homework assignment. (it does add a lot of work for the company to do homework problems well, but let's leave that aside)
the downside is that the candidate has a limited amount of time to talk to you. they often have a full-time job going on top of the job hunt. secondly, are you really game to spend 0.5-2 days of unpaid work just for the chance of being invited to interview further?