Why Kevlar watch straps?

I think it's mainly because it's "cool" to have a
watch strap made of a high-tech material.

It does have the advantage compared to some other
common materials that it's quite fire resistant so it doesn't
burn and melt, and this can be a good reason to choose
Kevlar over Nylon.

Kevlar is strong, but how often does that matter in this
application?
Besides, it looses strength if wet (which is restored
when it dries), so I don't think neither strength nor fire
is on the mind of those who use Kevlar "dive" straps,
and it looses some of its strength if you bend the
fibres too much (admittedly I don't know if normal use
as a watch strap influences this, but I'm sure it doesn't
enough to matter) and if subjected to UV radiation.

So, apart from the one advantage,
and that it's quite wear resistant, it doesn't seem like
Kevlar is an ideal material for watch straps, but when
that advantage is needed, it's possibly the best choice
today.

Is it Kevlar?

Some people have been investigating the material
"Kevlar" straps are made of. And it has turned out that
many aren't really made of that material at all.