The point would be to have a beer on the company dime and hang out with some of the folks that you will soon be flying with. They do quarterly socials in each base. These company socials are usually better attended than ALPA council meetings - although the beer is just as free at both events.
The company knows it will loose about 20% of the guys in the pool. This is just one small way that they are attempting to keep you engaged and in the pool until they give you a class date.