I have a pretty good idea of how long my build should take. If for some reason it takes longer (network issue, a bug in the build script or an infinite loop in some test code), I'd like to avoid it hanging and have it fail within a timeout that I can set. This avoids eating up build minutes from waiting until the full 2 hour limit.
e.g. I expect my build to take no longer than 5 minutes. If it takes longer than 5 minutes, it should just fail.
Ideally, this would be param that can be set in the bitbucket-pipelines.yml.