Not just for companies, but for cultural organisations and public bodies too.

For example, the Royal Opera House in London has an active and popular Youtube channel. They are a publicly-funded organisation but opera and ballet are still seen as somewhat elitist and expensive. Their Youtube channel gives them an opportunity to showcase their productions and behind-the-scenes footage. The videos are well-made and informative. And it undoubtedly helps bolster their reputation.

https://www.youtube.com/user/RoyalOperaHouse/videos

Another example: a well-known supermarket retailer in the UK (Waitrose) who also have a very polished Youtube channel (of mostly recipes)

https://www.youtube.com/user/Waitrose/videos

I think audiences are savy enough to know when a video has an element of promotion in it. What turns them off is if it feels like a self-congratulatory puff piece. Or if it feels too scripted and fake.