It takes a (small) village
There are three critical parts in the hotel website machine - understanding that the goal is to get business and the best rate from it.
For one, there's the getting-people-to-visit part. That's probably best done by two different groups: An advertising agency for brand advertising (re-targeting, targeted web sites, print, etc.) and a digital agency for things like social media, SEO and AdWords campaigns.
Not many creative agencies can really offer the same sort of technical knowhow as one of those digital agencies. And it's the rare digital group that really has the brand and creative chops you need.
Then there's the product. That's up to the client - the property. It's their job to make sure that there's something worth buying on the site; something people want, priced fairly.
And finally, there's the creative firm behind the website. Too often, this is left in the hands of that digital agency. Most digital agencies are real good at getting eyeballs to the site, but a little out of their element when it comes to developing and conveying the property's brand promise (which will get you a premium rate) or keeping those eyeballs on the site. That actually can be handled by the same creative agency that does the brand advertising. In fact, it's probably best handled by them.
Three distinct jobs. Best handled by three specialist groups.