I believe they like coming because they learn something and they dont have fun only.
How rude of you to assume that the other teachers who say FUN is important teach nothing else!
I believe for young children FUN is the best teaching TOOL available.
Here's an overview of what can be taught while the child is having FUN
1. Recognition of intervals, degrees, singing the higher lower or middle note in a harmonic chord.
2. Analysing, recognising, discussing, playing and explaing 'sections' of their piece using musical and very often Italian terms (my kids don't speak Italian by the way).
3. Understanding time signatures and how and why they work, key signatures and how and why they work, scale formulaes, both major and minor - and how to work out any scale they want without having to look it up in a book.
4. Scales, hands together, similar, contrary motion, chromatic - yes I'm talking at the preliminary level, arpeggios, however many octaves and positions you want to include.
5. Music history, when were the eras, what was life like in these eras, who were the composers, how were they employed, how did they live; what Purcell wrote and why we should care etc
6. Musical appreciation; developing an ear, and an opinion on what they like based on WHY.
7. Sight reading.
8. Aural skills.
9. Interpretation
10. Composition
11. Improvisation
12. Performing
13. How to practise
14. Setting goals; long term and short term
15. Organising time, self disciplin, self motivation, pride in piano accomplishment, detection of weakness and strength, implementation of strategies.
16. Enrolling, attending and receiving distinctions in music exams having only six months of lessons.
All this can be accomplished while the child is giggling happily and you are laughing and living longer for it.
I've taught in both primary school and high school before becoming a private music teacher. From the age of 9, I've wanted to be a teacher.
I did four years at Uni to be qualified specifically as a teacher, not a performer. I give my time, my energy, my priority to my students. I know HOW to teach because I've been taught in THAT area, and I received the highest marks in all subjects. So rest assured, when students come to me, their parents may take me seriously. Their kids will learn and progress more rapidly than any other teacher in my area (I know this because I have been told by MANY people, and I tend to believe them because even I'm impressed with the results my kids get for their music exams). AND they had LOTS of fun in the process. I have lots of fun in the process.
Do not assume any less from the other piano teachers who also confess that for them music and teaching is FUN.
The fact that you are annoyed at this is a sign of either jealousy or arrogance.