Katanas are traditional Japanese swords. Lightsabers are also some sort of swords with laser blades. So, you can call them lightsaber Katanas too and can buy one at Zia Sabers.

Gira was a Jedi Knight who served during the Clone Wars. He wielded a special type of lightsaber with a design of sword known as lightsaber Katana.

The Darksaber is one of the most unique lightsabers. It emits a laser blade, but the blade is of traditional Katana design, unlike other lightsabers.

They did in ancient times. However, with time and the invention of lightsabers, the traditional swords were no good anymore.

A lightsaber can cut through everything with the exception of a few materials. Swords are mostly metals, so lightsabers can easily cut through the swords.