I really don't think build time is very important. With a separate CI server it doesn't much matter if takes an hour or <10 minutes for a build to complete, the gain for me is that it's no longer "your" time. It's some other server that's doing the work with a saved state (master).

I'll typically just merge into master on GH, let the CI server take it from there and not bother checking the site manually when the build is complete, it's not necessary. Our QA and CI process handles that.

I consider it a major advantage (benefits far outweigh risk) that I can typically merge my ticket into master, close my laptop and head home.