Why would you need boots to fly a plane off bitumen runways and from terminal buildings?
You don't
need them but when they are very comfortable and last for yonks, why wouldn't you?
I had 2 pairs of RM's in the last 25 years of my career. The first I replaced after 15 years of almost daily wear as I was too lazy to send them in and get the elastic replaced and the second pair are still in very good condition although not worn nearly as often as they were up until 2 years ago when still working.
I noticed some when I followed Mrs C441 into the RMs outlet store down the coast recently. They were $399 Craftsman boots with a mark in the leather about where your achilles meets your ankle; so hardly noticable that I nearly bought 'em.