I'd say it's probably the single most important question. Engineering is about trade-offs; understanding which trade-offs are acceptable means understanding wh

I'd say it's probably the single most important question. Engineering is about trade-offs; understanding which trade-offs are acceptable means understanding what it is you're trying to solve; then assessing whether the problem is being looked at from the correct point-of-view (and for that matter whether it's even a technical one). For example: Journalists within hostile nations are risking their lives every day. Because of this, they're keen on keeping their communication private and away from prying eyes. So far, the compromises largely involve zero-days and social engineering. The former is really due to the shaky foundation of software today. Every single best practice I see is just awful. Whereas social engineering is an on-going problem and is a policy/procedural/cultural problem, not a technical one. The union of bad software and tolerant social protocols make privacy difficult. Going back to your objection: For use cases where your life is on the line, is a few seconds or even minutes of latency really a problem? Extend the question, for cases where it's not life-threatening but life-altering. What trade-offs are most users willing to make then? If you're not willing to make any trade-offs no matter what, then it's difficult or even impossible; and also a sign of a poor engineering process.