Security transformer, what do you need it for?

Moin Forum, as driving away is currently falling into the water for known reasons, I went to my caravan and looked at what is under the “hub”. So far, there was no need to do this, everything is running. Lower bed box is mounted the majority of the electrics. Battery, Dometic control center, mover control, 12V and 220V distribution boxes. What I can’t do with is a safety transformer from Weiss. Input voltage 220V AC, output voltage 26V AC. I don’t have a plan to go where the lines go. Why do you need 26V AC in the caravan? 12V DC I could understand for the 12V consumers at Landstrom (where there is the Dometic for that…) Can someone bring some light into my dark. I bought the WoWa used a year ago. Nice weekend…