While I agree not everyone 'needs' the grip a 5.10 gives - it depends on riding style and the pedal - there is nothing better when it's wet and muddy. The more aggressive you are, the more you'll appreciate the mega-grip in chundery sections that try to shake your feet off the pedals.
While not everyone 'needs' armour on their shoes, just see what happens when you sandwich your toe between your pedal and a rock or protruding root on the ground as you glide by doing 40 km/h. It hurts. Sofa king much.
Not everyone does long hike-a-bikes, or often, but there are some scenarios where Vans won't be great, XC slippers with plastic soles suck, and only a decent tread will do.
I'm a bit of a shoe obsessive, and maybe some aren't the best looking but I do think there are some good options. 5.10s got way lighter, less bulky, and better looking. Clipless shoes come in better options for the trail rider that pedal well, hike well, and look decent.
There is a lack of good shoes for flat pedals, though. The Tevas are decent unless it's wet. The Giro Jacket is actually pretty good. The Spesh 2FO works well. 5.10 of course. But that's about it. There is a teaser out there about a new flat shoe that's supposed to be the cat's ass. I guess we'll see soon enough.