I think that there are two ideas worth separating in this post.

1. Having ready beer (a keg) available in a work setting can cause issues. Ready alcohol impairs judgement and blurs boundaries.

2. Having Friday afternoon beers (or any other kind of gathering) can be beneficial to company bonding and communication. Frankly, I don't care if it is ice cream (as suggested in the comments), beer, weekly lunches, or kite flying--I want a regular low pressure social atmosphere for a) getting to know my team mates and b) exchanging work ideas in an informal cross department setting.

I think having types of events outlined in point 2 is beneficial to everyone in the company.

Disclaimer--I work in a small company that does Friday afternoon beers, but we are not a startup.