It's entirely possible to be highly competent and not yet ready to lead. Skill can be built quickly, sometimes in a single season. Character takes longer — and leading ahead of it eventually shows, no matter how sharp the skill is.
“...temperate, sober-minded, of good behavior, hospitable, able to teach; not violent...not greedy for money, but gentle, not quarrelsome.”1 Timothy 3:2–3
Scripture's own qualifications for leadership are worth noticing for what they emphasize. Self-controlled, hospitable, not quick-tempered, not a lover of money — almost entirely character, almost nothing about skill or track record. That emphasis is a real signal, not an accident.
A leader with competence but no character eventually manages people. A leader with character eventually forms them. The difference rarely shows up in a job interview — it shows up under real pressure, when something actually costs the leader something.
This is exactly why the six stages place Become before Steward. Competence gets the chance to develop honestly on top of character already in place, instead of being asked to cover for character that hasn't been formed yet.