Ugh. This mentality is fine when you want to ship an MVP but it's absolutely poisonous to the team and the project if you hold on to it. You need some slack for people to address the problems they think need solving without needing to justify why they're solving it. From a team perspective, it helps prevent burnout and encourages development, and from a project perspective it's essential to preventing management-driven tunnel vision by allowing the team to explore and prove out things that management doesn't understand yet. I've seen a lot of data-driven projects starve because of a fear of collecting new data, and it's totally invisible to management because they're hitting the KPIs they set for themselves.

Prioritize, yes, but don't starve lesser priorities. Let individuals decide, say, 10%-20% of their effort spend and don't question it. That figure, conveniently, corresponds to the Friday they're spending not productively working anyway.