In flight fire would be the worst thing. However it is most likely to be electrical and very likely to go out if you pull the main CB.
That's why I carry a battery powered GPS (two actually; the 2nd one would fetch zilch on Ebay and might be handy in the life raft...) and an Icom radio. I bought the Icom radio the day after I got a radio failure during a pre-PPL solo flight. I know one can fly non-radio but some things in life have a really trivial solution so why make life hard?