My husband and I started off as friends, and I was his date to his company's Christmas party for the first couple of years when we were just friends. I definitely cite these parties as part of the reason we ended up getting together.

However... I would not recommend a work party as a first date. If you want to bring a plus one to a work event, it should be someone you trust to make you look good. So if you're not seeing anyone exclusively, you should bring a friend that you know will talk you up, not drink too much and hit on your married boss, etc. You get the idea.

Work events can be boring, so inviting someone who you can still have fun with guarantees a good night regardless of how the party plays out.

The fact that my husband and I ever started dating after a few years of just being plus ones for work events is a bit of a fluke, but the fun we had as friends definitely translated to fun as a couple, and I wouldn't take that back for anything in the world.