Suburban DSI Water Heater Q

Hey all
About 3 days the electric element on the wh quit working.
Started troubleshooting today.
There is an on/ off toggle switch which was frozen, so hubby took it out and the wires were burnt.
Cleaned wires up, tied them together, and the electric element works.

Question... Is that switch on the outside needed, since we have one inside to control both the electric and propane?

Hubby doesn’t see a logical reason for it, since we don’t winterize, and she’s never in storage.

Thanks in advance