There's really two schools of thought on this.
One school of thought says that making shorts is your lifeblood to practicing and honing your craft. It's easier prepare, easier to get a team together for a day/few days to shoot something short (especially on a volunteer basis), and post production than it is to get volunteers for a 10 to 30 day (or more) to shoot a full feature.
The other school of thought (though much less common) is why spend even a dollar on something you will never, ever have any realistic expectation to recoup expenses, let alone make a profit. This school says, make a movie. Learn along the way and you never know, once you finish, there is a chance that you have a product that you can sell to a distributor, perhaps even solidly launch your career. If you're making a product that you can sell, this also opens the world of investors to you, which won't happen with shorts.
Going through the process of finance and distribution, you're learning the business side of the movie business. It's a very important, often ignored part.
Shooting shorts is more appealing these days than it has for a long time due to Youtube. There are people out there making a living shooting short videos, garnering a large following and taking their share of advertising revenue. Creating one or two off shorts isn't going to make this work, you'll need a plan for constant content to keep your following interested.
