I think they are saying the app could be a pre-commit hook where their API is hit before code goes up to remote
If a user is offline, they are not going to be able to push code for review anyway. Either way, it seems prudent to shift validation and checks closer to the developer, before pushing code. Otherwise you end up with a series of commit & push, wait for check, commit & push fixes, wait for check, commit & push more fixes...
Why does that matter?