This may not have occurred to you, but it's an investment of time both ways. The company most likely spent >2 hours of staff time filtering resumes, & handling communications before issuing the code challenge.

If a fizzbuzz-order phone screen was done before the longer coding challenge, for multiple candidates, then most likely >> 2 hours.

What sucks though is when the hiring manager pretends (as managers often do) that the challenge will take "only 2 hours", but in reality -- to get it production-grade, well-document, and (as happens quite often) provide fixes or workarounds to bugs in the hastily drawn up spec -- it ends up taking 5-10 hours.

And as a reward, you get sent back to the internal recruiter, with their finite attention span and short-term memory capacity. And the usual random delays, inattentiveness, and cognitively detached communication loops ensue, for week after week.

Fun for everyone!