For many less frequent travelers considering about what their bag is made of is often less of a concern than eg a person who travels frequently over medium to long distances. People who travel long distances eg using airports are often more kindly to consider quality and durability of materials as well as style in their choice of bag / luggage. This type of traveler may also be less price-sensitive and more proactive when it comes to purchasing their bags.
Nylon Travel Bags
Since Wallace Carothers of DuPont reportedly invented nylon in the late 1930s, its many advantages and potential applications have meant that it and other man-made polymers and materials have been used in almost every aspect of our lives. The fact that it is man-made materials like nylon give tremendous flexibility in the shapes, sizes, and colors that can be made from it, and the designs, decoration and printing that can be added to it. The uniform chemical and manufacturing process of nylon and its flexibility as a material means that the finished product can be made very uniform eg in color, thickness, consistency and quality. Although a strip of nylon has strength because of the way the many fine nylon strands fit together, and because of a degree of 'give', it is often thin enough to make it relatively easy to stitch or bond together. Producing the type of nylon material used in travel bags is often a large scale process and this and some of the factors already mentioned mean that nylon is a relatively cheap material to use in the manufacture of other items eg travel bags. This brings the cost of nylon based travel bags down to level that's relatively affordable to all. Nylon is a flexible material, and reliably durable as longs as it is not exposed to sharp objects, heavy weights and awkward shapes / awkward shaped objects inside the nylon travel bags. Unfortunately, lower quality nylon bags sometimes do not have strong or high quality zips, seams, straps, handles or pockets, and as such their lifetime can be shortened by the failure of any of these parts, and the fact that it is illegally to be worth the price of repairing any of them if / when they break.
In terms of design the variety of modern leather travel bag designs and features means that the choice is now incredibly wide. Although the range of colors may generally not be as wide (or the demand for certain colors may not be as wide) the colors used in modern leather travel bags tend to play tot the strengths of this unique material and bring out the best, and the most tasteful aspects of it. Since good quality, thick leather hides are ach only big enough to make a relatively small quantity of bags, each bag is likely to have its own level of individual eg slight color difference and sometimes 'range marks'. Since full grain high quality leather really undergoes minimal processing eg hair removal and tanning, the marks / scars made on the animal's skin during life eg from wire fencing, insect bites etc, may still be just evident in some sections of leather. This individuality and authenticity is part of the beauty and appeal of leather travel bags.
As a material, leather is very strong and resistant to scrapes, scratches and bumps. It also provides an extra degree of protection for the contents within the bag that nylon does not. High quality leather travel bags tend to have very strong stitching, strong zips which have leather pullers. There are also tend to be generous cargo spaces in these bags, and they tend to have many other practical and handy pockets eg flap-over pockets with magnetic studs and zipped pockets. Storage pockets for laptop computers are now also commonplace in these bags. The bottom of high quality leather travel bags are often protected with domed metal studs, the anchor points are usually extra secure, and any straps are often detachable with comfort pads. The handles also tend to be very strong with wrap-around leather comfort pads in many cases. Obviously, for quality of this kind you may expect to pay more than for their nylon counterparts. However, leather travel bags tend to be much more durable and hard wearing, and over the lifetime of the bag (which could literally be a lifetime) they actually work out to be reliably inexpensively. Leather travel bags also seem to create the right balance between style and practicality, and never seem to go out of fashion.