People who use the underground train ssytem on a regular bases opt for the card, as it can be recharged on your phone through the Bonjour RATP app, at a metro station ticket office or kiosk. The traditional ticket can only be purchased at a Métro station and can be more of a hindrance at times. The first thing to note is that Métro tickets are small and thus can be lost easily. They also can't be anywhere near the back of your phones as the tickets can become invalid that way. This can be a problem if you are randomnly asked to present your ticket to a transport officer or if you need to exit the Métro, as some Métro and RER lines station require that you use the ticket for entering one station to be used to exit another station.
Paris public transportation is designed to help people around more easily, in greater comfort, and more safely. As Paris is such a heavily populated city with each ground meter of the city serving a purpose to the general population, public transportation is invaluable to many of its residents and is a big help to tourists trying to get from one site to another cheaply and quickly. However, interestingly enough, real Parisians often say that they hate the Métro due to it being overcrowded, prefering to take cars on a regular basis. Another thing to add is that in recent years, the French people and government have grown very passionate about protecting the environment, thus Ile-de-France Region have invested more than 200 million euros to encourage the use of bicycles.
