Munich is a magical place in December. I think the Munich Christmas markets are one of the only reasons I can handle not going home every year for Christmas. Since I am married to a German we rotate where we celebrate Christmas. This is a Munich year and that works out well since we just had our baby boy and are not ready to travel yet.
Most adults are excited by the Christmas markets because it is a nice place to share a glühwein with friends or colleagues after work. Moms are excited by Christmas markets because it is something to do in the cold month of December when you can not face another afternoon of arts and crafts.
There are so many Christmas markets and most have some type of carousel ride for young kids. I never just buy one ride especially to the ones that we walk by more frequently I will get the 10 pass at the beginning of December and give the kids each 2 rides each time we go.
Two of the other Munich Christmas markets I recommend to visit with kids are the Chinese tower Christmas market where they have story time with Oma and Opa’s building workshop. https://www.weihnachtsmarkt-chinaturm.de/
The Residence Christmas market has times when you can see a kasperltheater and also a Christmas village with moving and music playing displays. http://www.dasweihnachtsdorf.de/