They'll likely type a query in their own language and to respond to that query you'll need content in that language.
What about using free machine translation on your hotel website? Besides the fact that poorly translated content could actually hurt your brand, machine translation widgets don't provide any SEO (search engine optimization) benefits, since they only translate "on-the-fly", and search engines can't index their output.
Foreign language content also gives your hotel more prominence, meaning more mentions in foreign language social media, as well as more listings in hotel, B&B and inn web directories and aggregators.
Even if your international guests speak English and they manage to find you online, they'll likely warm up to content in their own language. It may just be that final factor that helps them choose your property over a competitor's hotel that does not yet have a site in their own language.