We don’t recommend that you let your cat drink beer. It is a depressant and is unhealthy for your cat.
Your cat likes beer for the same reasons that adults do — it tastes good!
I have personally witnessed a cat that loved beer so much that he would knock the bottle off the table, just so he could get a small taste while the owner cleaned it up.
It is possible that cats like beer because it is generally made with malt. Cats love malt! Malt is used for flavoring in many cat treats. It is also used to flavor many types of hairball prevention pastes.