Doesn't matter what kind of job it is, you can be pretty much 100% guaranteed that the job will be listed on the company website without any of the extra hoops to jump through.
Requiring someone to build a web app just to apply is a huge requirement. It's fine if you gave someone an interview, and this is the final step before you hire...but requiring someone to code just to submit an application is abuse.
I can see this as a useful tool for pre-phone screen or post-phone screen evaluation. At the startup where i work we do send the candidate a small code problem after the phone screen and before the on-site interview. I know lot of companies do that. Gives you a little more insight about the candidate and also ensures that you are not wasting your teammates' time as well as the candidate's time.
Also, submitting the resume/github link along with a solution to a programming challenge increases the probability of getting to the phone interview stage. Highly applicable for famous companies like FB or twitter where they receive hundreds of similar applicants every day. Of course it is a stupid method if you are trying to hire a team lead or senior engineer but for fresh graduates or junior developers it works well. I don't think they will mind spending an hour solving a problem.
As someone who hires I want to know what they can do vs what they say they can do. When I hire I ask job applicant to cut up and code a PSD. Some refuse while the eager ones whom are really serious and are excited about the job happily do so.
Overall it's good practice and we give each applicant feedback on how to improve. The flip side allows us to see who cut up and coded the PSD the best (validates) and quickest. That is the person we go with; majority of the time.
Jobs aren't easy to come by these days and in non metropolitan cities the competition is fierce.
You judge job applicants by their willingness to jump through boring scut work hoops in the hope of getting a job? I don't know what you're optimising for there, but it certainly isn't programming talent.
I've known a few C-class bumblers who would probably do that for a job interview. The number of grade-A talented engineers, the people I would want to hire, who would put themselves through some pointless, arbitrary slog just to impress you with their "eagerness"? Precisely zero.
There are tons and tons of resumes and the shop is not located in a huge metropolitan area like San Fran, NYC, Chicago, etc.