Most ear-training apps are multiple-choice quizzes. You hear something, you tap a label. You get good at recognising labels.
Good Ear is built for the other half of the skill. You hear an interval, a chord or a melody in real harmonic context, with the home chord ringing under it, and you play it back on a real piano keyboard. The same skill you use when you transcribe a solo, sing a part you've never seen, or hear a chord change for the first time.
WHO ACTUALLY USES GOOD EAR
• Self-taught musicians who've hit the plateau where their ears can't keep up with their playing
• College and conservatory students preparing for aural-skills, theory or entrance exams
• Jazz players, producers and session musicians who transcribe by ear
• Vocalists and instrumentalists learning to sing and play what they hear
• Teachers and educators looking for a structured aural-skills tool…
From the developer’s store description.