A full, timed practice run built to match the real thing: the same question count, the same time limit, and — where the vendor publishes one — the same per-domain pass structure. No hints, no explanations mid-exam. You find out where you stand the way you'll find out on exam day.
A single pass/fail score tells you almost nothing about what to fix. Every result comes with a per-domain breakdown, so a passing score with one weak domain looks different from a passing score that's even across the board.
Every question you get wrong is added to your repeat list and shows up again in both flashcards and training mode until you've demonstrated you've got it. Exam mode also teaches the platform what you personally need to review.
A diagnostic run before you start studying, to find out which domains you can skip and which need real time. And a final readiness check in the last week before your real exam date, under conditions close enough that nerves aren't a surprise.