Putting children into ski school is generally beneficial to both children and parents. Kids meet others of a similar age and ability, while developing their ski abilities in a safe and progressive manner and it lets parents have some time to themselves to ski. This is all of course providing the school knows what they are doing.
Things to check for in a ski school
Are the teachers qualified? All countries have a national body that trains and licenses instructors. They will have learnt various teaching progressions, how children develop and games and exercises suitable for different ages and ability groups. Some schools however employ unqualified instructors.
Generally instructors who are the same nationality as the children will understand not only the language but also the culture and body language better than non-native instructors. Check that the instructor has experience teaching kids. Techniques for teaching children can differ from adults.
Dedicated area etc.
A separate area for children helps them to get the most out of the lesson and is safer. A selection of equipment such as hoops, cones, balls, mats and poles help the instructor keep the kids interested and makes it easier to set targets and measure achievements.
Make sure the ratio of kids to instructors / helpers is good 8:1 is ok for older kids but it should be less for younger ones.