is it worthy to invest in good hotel related domain names? do hotel buy parked domain .. any experience about it or suggestion?
Depends on domain. There is a small possibility someone could buy your domain but chances are not very big, maybe if it is really good and if you offer it to someone instead waiting for buyer to contact you.
If you know a hotel is going to be built in a specific area then it might be worth getting a domain. So if you know company x are building a hotel in Rome then get domain x-Rome.com. Otherwise most big hotels have their own domains already. Small hotels will just buy some other domain and don't have the budget to buy expensive domains.
I'd say hotel domain names are pretty popular - they're always in demand as new travel websites are showing up on the web everyday. But make sure the domain you buy isn't more than 2 words.